- Business in Poland -
Evidence in a Commercial Dispute – What Matters Most and How Not to Lose on Technicalities
Evidence in a commercial dispute covers any means of proving facts that matter for deciding the case and that are admissible in civil proceedings before a court or in arbitration. In practice, it is not enough to “be right” - you must be able to prove you are right under the procedural rules, including within the required deadlines and in the correct format.
In business disputes, what is at stake may include cash flow, reputation, and contractual security. That is why it is crucial to understand how the burden of proof works, which evidence is most often decisive, and where it is easiest to lose due to procedural formalities.
Burden of proof and the evidentiary proposition - this is where winning begins
The basic rule is: whoever alleges, generally must prove. This follows from Article 6 of the Polish Civil Code [1] and Article 232 of the Polish Code of Civil Procedure [2]. In a claim for payment, a business should prove not only that an invoice was issued, but above all performance, the contractual basis, the amount due, and that the claim is due and payable.
An effective evidence strategy requires a clear evidentiary proposition - i.e., specifying which fact is to be proven and by what evidence. Without this, the court may treat the material as chaotic and deem part of the evidence irrelevant (Article 227 CCP [2]).
Evidence preclusion - the risk of losing your chance to use key evidence
In commercial cases, evidence preclusion is particularly dangerous - the risk that late allegations and evidence will be disregarded at a later stage. Civil proceedings are based on the concentration of procedural material, meaning a party should submit allegations and evidence as early as possible, in particular in the statement of claim and the statement of defence, and in submissions filed within deadlines set by the court during the proceedings (Article 2053 CCP [2]).
The court may disregard late evidence if it is submitted after the deadline without a justified reason or if it would cause undue delay. In business reality, the mistake often lies in assuming that “we’ll submit the documents later” or “we’ll name witnesses if the other side denies it.” That approach can be costly.
Three exceptions when late evidence may still be admitted
In practice, the procedure provides situations in which the court may admit evidence submitted later. Most often, this applies where:
- the failure to submit the evidence on time occurred through no fault of the party,
- admitting the evidence will not delay the hearing of the case,
- other exceptional circumstances justify admitting it.
Most common evidence in B2B disputes and their “traps”
Email evidence in court
Email evidence in court can be decisive in proving commercial arrangements, acceptance of the scope of work, complaints, or agreed changes to deadlines. There are two key risks. First, missing continuity in the email thread and attachments. Second, disputes over authenticity or whether the correspondence related to the specific transaction.
In practice, it is worth securing complete threads (with headers), attachments, and delivery/receipt confirmations, and maintaining consistent subject lines. In higher-value cases, it makes sense to organise correspondence chronologically and describe it in the evidentiary propositions.
Invoices and proof of delivery/acceptance
Invoices and proof of delivery or acceptance are common in payment disputes, but an invoice alone usually does not determine whether a claim is justified. What matters are documents confirming performance: acceptance certificates, delivery notes (WZ), consignment notes, signed purchase orders, service reports, system access confirmations, and milestone approvals.
If acceptance was “silent” (no objections raised), it is worth showing the acceptance procedure under the contract, the deadline for reporting defects, and the fact that the deadline expired without a complaint. If a complaint was made, you must show its scope and its impact on remuneration (e.g., set-off, price reduction).
Recording a conversation as evidence
A recording of a conversation as evidence appears increasingly often, especially where arrangements were made by phone. In civil proceedings, the court assesses evidence freely (Article 233 CCP [2]), but that does not mean a recording is automatically effective. Key issues include identifying the speakers, the integrity of the recording, the context of the statements, and consistency with other evidence.
You must also consider legal risks outside the civil case itself (e.g., allegations of infringement of personal rights or issues related to data processing). Whether a recording is admissible and useful depends on the facts, so the decision to use it should be preceded by a risk assessment.
Witnesses in commercial litigation
Witnesses in commercial litigation may be necessary when documents are incomplete or the parties made oral arrangements. At the same time, in B2B disputes, courts usually prefer documents and correspondence evidence, and employee testimony may be viewed through the lens of organisational dependence.
For a witness to genuinely help, you need to precisely identify the facts they are to confirm and avoid “witnesses for everything.” It is also worth preparing for questions about internal procedures (who approved the order, how acceptance was handled, who conducted the negotiations).
How to prepare evidence so you do not lose on procedural technicalities
A practical approach to how to prepare evidence in a commercial dispute can be reduced to a few steps that minimise the risk of evidence preclusion and disputes over completeness:
- Claim map - list the elements you must prove (contract, performance, value, due date, lack of an effective complaint).
- Timeline - a chronology of events with references to documents and emails.
- Evidence bundles - one topic, one set: order + confirmation + performance + acceptance + invoice + payment demand.
- Versions and metadata - keep original files, contract versions, and change history; avoid “rewriting” content into new documents.
- Consistency with accounting records - ensure amounts, dates, and payment references match bank transfers and the invoice register.
Evidence in commercial disputes before courts and in arbitration
The choice of dispute-resolution forum affects evidence tactics, deadlines, and expectations regarding documents. In court proceedings, procedural discipline and early concentration of allegations and evidence are key. In arbitration, there is often more flexibility, but the quality and consistency of the evidence still decide the outcome.
In cases where the commercial relationship is at stake, evidence is scattered, and there is a real risk of preclusion, it is often sensible to quickly organise documentation and assess whether the dispute can be settled amicably without weakening the litigation position - which remains one of the areas of work for teams handling commercial disputes.
This material is for informational purposes only and does not constitute legal advice; in cases where deadlines and the risk of evidence being disregarded are critical, a prompt review of litigation strategy may be advisable - therefore it may be worth arranging a consultation via https://www.kkz.com.pl/.
FAQ: Evidence in a Commercial Dispute
1) Who bears the burden of proof in a commercial dispute?
As a rule, the party that derives legal effects from a given fact (Article 6 Civil Code [1]). In civil litigation, the parties are required to indicate evidence to establish the facts from which they derive legal effects (Article 232 CCP [2]).
2) Are emails enough to prove commercial arrangements?
Often yes, but it depends on the completeness of the thread, identification of the parties, clarity of the content, and the link to the order and performance. In practice, emails should support transactional documents (purchase order, acceptance certificate, invoice).
3) Is an invoice proof that a service or delivery was performed?
An invoice alone usually does not prove performance. The greatest weight is given to evidence of performance and acceptance: certificates, delivery notes (WZ), consignment notes, milestone approvals, reports.
4) Can a call recording be submitted in court?
It may be used as evidence, but its usefulness depends on the circumstances: authenticity, integrity, context, and its connection with other evidence. In addition, legal risks related to how the recording was obtained and used must be assessed.
5) What is evidence preclusion?
It is the risk that the court will disregard late allegations and evidence if they were not submitted at the appropriate stage of the proceedings, in particular in initiating submissions and within deadlines set during the preparatory phase (Article 2053 CCP [2]).
6) What are the most common mistakes when preparing evidence?
Scattered files without chronology, missing email attachments, lack of acceptance/delivery proof, inconsistency of amounts with accounting records, and “saving evidence for later,” which increases the risk of evidence preclusion.
Bibliography
- [1] Act of 23 April 1964 - Civil Code (Journal of Laws 1964 No. 16, item 93, as amended), Article 6.
- [2] Act of 17 November 1964 - Code of Civil Procedure (Journal of Laws 1964 No. 43, item 296, as amended), Articles 227, 232, 233, 2053.
Author: adv. Maciej Zaborowski, Managing Partner
E-mail: m.zaborowski@kkz.com.pl
