Don’t be thrown by a company’s response to your complaint. Martin Lewis' guide on how to complain about something you bought, or a service provided. It explains your rights & how to use them to get your money back. Rule 6: Expect the unexpected. You can make a formal complaint in any of these ways: Speaking to someone and telling them that you would like to make a formal complaint, as well as telling them what it is about. If you’ve complained effectively, you may well get a much higher level of response than you were expecting. If you do this, the organisation is allowed to write down your complaint themselves and they must give you a copy of their written record. Make sure that you have spent time crafting your tweet carefully to express the nature of your complaint, or saying how long it has taken to respond to your original complaint.