An unpaid invoice can quickly become a distraction for a business owner. Before sending a stronger reminder, it helps to establish what is owed, when payment became due and whether the customer has raised a genuine dispute.
For international businesses operating in Bulgaria, the relevant information may be spread across an English-language contract, purchase orders, delivery records and correspondence between several teams. Bringing those documents together is a useful first step.
This guide concerns business-to-business payments. Consumer debts and public-sector contracts may require a different assessment.
1. Confirm which company owes the money
Check the legal entity named in the contract against the purchase order, invoice and correspondence.
A trading name, a group email address or instructions from a parent company do not, by themselves, resolve which entity is responsible for payment. Record the customer’s registered name, registration number and address, together with the details of your own company as creditor.
Where the relationship involves companies in different countries, identify any governing-law and dispute-resolution clauses before assuming that Bulgarian law or Bulgarian courts will apply.
2. Establish the payment deadline
Start with the agreed payment terms. Does payment run from the invoice date, receipt of the invoice, delivery or acceptance of the work?
Check whether the customer received the invoice and whether the contract requires supporting documents or submission through a particular portal. If payment depends on a milestone or acceptance procedure, gather the relevant records.
Do not assume that a date printed on an invoice settles every question about when payment became due. Under Bulgarian law, the applicable contract and statutory rules need to be considered together.
3. Gather evidence of your performance
Put together a short, organised file containing:
- The contract, applicable terms and purchase orders.
- The invoice and evidence that it was sent or received.
- Delivery records, acceptance documents or evidence of completed services.
- Approved changes to the scope or price.
- Payment reminders, replies and records of any partial payments.
For services, useful records may include agreed deliverables, progress reports and correspondence confirming completion. Preserve the original records and their dates.
The aim is to show how the agreed work, the amount invoiced and the payment obligation connect.
4. Separate a payment delay from a dispute
Has the customer simply failed to pay, or are they challenging the work, the price or part of the invoice?
Ask for a specific explanation and identify which amounts are disputed. A complaint about one deliverable should be recorded separately from a general request for more time to pay.
Before agreeing a discount, credit note or instalment plan, consider how it affects the outstanding balance and the wider contractual relationship. Record any agreement clearly, including what remains payable and when.
If you are considering suspending services or terminating the contract, obtain advice on the available grounds and required procedure before acting.
5. Check interest and recovery costs before adding them
For commercial transactions governed by Bulgarian law, Article 309a of the Commerce Act provides for statutory late-payment interest and compensation for recovery costs of at least €40 where its conditions are met. The creditor must have performed its obligations and the debtor must be in payment default. Contractual provisions also need review. A reminder is not required for those entitlements under that provision.
This does not establish that every unpaid invoice automatically qualifies. Check the applicable rules, the start of default and the calculation before demanding additional amounts.
6. Choose a proportionate next step
A payment reminder should identify the invoice, outstanding balance and basis for requesting payment. It should also give the customer a clear way to respond.
A formal demand may require more careful wording, delivery arrangements and a review of the available next steps. Do not assume that continued reminders protect a claim indefinitely: limitation periods and procedural deadlines need separate attention.
If late payments recur, review the process before the next invoice is issued. Clear payment terms, documented acceptance, controlled changes and an agreed escalation process can form part of ongoing legal support for your business in Bulgaria.
Preparing for a legal discussion
Start with a brief summary: the parties, the amount outstanding, the payment terms, what was delivered and the customer’s explanation.
To discuss an overdue business payment or recurring contract support, send an enquiry or email office@petrov-bg.com. Please wait to send confidential documents until arrangements for reviewing your matter have been discussed.
General information, checked on 4 November 2026. This article does not replace legal advice on a particular contract or claim. An enquiry does not establish an attorney–client relationship.