Do you not wish to use mediation through an ombudsman service, or has mediation failed to resolve your dispute with the business? You can always initiate legal action. Please note that court proceedings are often time-consuming and expensive.
The magistrate's court is generally competent for claims up to 5,000 euros.
The court of first instance is competent for claims over 5,000 euros.
The commercial court is also competent in many cases.
You can find which court is competent for your case on the FPS Justice website.

