If the complaint can't be resolved
The suggestions so far focus on a system for handling dissatisfaction expressed to a retailer by a customer. It is preferable to try to settle the problem with the complainant early rather than allow it to escalate into a larger and more difficult dispute.
If the complaint can't be resolved it may be necessary to refer the matter to other, sometimes more formal, procedures for dispute resolution.
Dispute resolution aims to deal with problems which cannot be resolved within a complaint handling system. Consumer Protection can provide further information about dispute resolution.