What evidence do you need for an unpaid invoice?

The agreed terms — a signed contract, a purchase order, accepted terms of business, or an email agreement — establish what was agreed, at what price, and on what payment terms. This is the foundation of the debt.

The invoice itself: number, date, amount, due date, and what it covers. A statement of account showing the outstanding balance and any part-payments helps reconcile the figure.

Evidence that the goods or services were delivered and accepted — delivery notes, sign-offs, timesheets, completion confirmations, or correspondence acknowledging the work. This counters a “we never received it” defence.

A dated trail of reminders, replies, and any chase calls. It shows you gave the debtor a fair chance to pay and records what was said on both sides.

Any promise to pay — a date, a part-payment plan, an acknowledgement of the balance. Promises both move the case forward and strengthen the record that the debt is accepted.

Whether any part of the invoice is genuinely disputed, and how that dispute stands. Recording this honestly matters: the courts expect disputes to be addressed before escalation, not ignored.

Companies House verification means checking a limited-company debtor's registered name, company number, registered office and status against the official Companies House register before you escalate. It confirms you are pursuing the correct legal entity at the correct address. WolfX uses these details to label the debtor accurately in your evidence; it does not change the register.

If you have sent a Letter Before Action, keep the letter and a record of when and how it was sent. It evidences that the formal pre-court step was taken and the deadline given.

WolfX stores these records in an Evidence Vault with an integrity trail, so the account of the debt — who owes what, why, and since when — is clear, consistent, and easy to review. WolfX is software; it does not provide legal advice.