If you are in a dispute
If the business is unwilling to resolve the issue to your satisfaction, your first step should always be to formalise your complaint by putting it into writing, giving them a resonable time to respond. If you don't receive a satisfactory response, you may want to esculate your complaint to the managing director or proprietor of the business and follow the businesses complaints procedure. If the matter is still unresolved you may wish to enforce your rights through alternative dispute resolution (ADR) or through the court.