Which court or tribunal should I use for an unpaid invoice?

The right forum depends mainly on the amount. Claims of up to 30,000 dollars can be brought in the Disputes Tribunal, which is informal, inexpensive and usually does not involve lawyers. Claims above that, up to 350,000 dollars, go to the District Court, and larger claims to the High Court, both of which have more formal procedures and higher costs. Before filing, send a clear letter of demand giving the client a deadline, since courts expect you to have tried to resolve the matter. Keep your contract, invoices, emails and evidence of the work done. You can act for yourself in the Disputes Tribunal, but for larger claims a lawyer is usually worthwhile. If the client is a company, check its status on the Companies Office register.