Try to resolve the dispute by explaining your problem and what you want done about it. If the company has its own internal complaints procedure, follow it.

You should give the company eight weeks to resolve your complaint. 

If the company refuses to do what you ask to sort out the problem, ask for a ‘letter of deadlock’ to show you've done all you can to resolve the complaint. 

If the company fails to respond to this final letter within a reasonable period of time (say, 14 days), you can take your complaint to the FOS.

You must take your complaint to the Financial Ombudsman Service within six months of receiving this letter, otherwise they may not be able to help. 

Contact the FOS to find out how to submit a complaint.

The Ombudsman will ask you to fill out a complaint form which you can find on their website.

They can help you do this over the phone if you'd prefer to talk it through with someone, on 0300 123 9 123 or 0800 023 4567.

The FOS will look at the evidence provided by both sides. It might contact you for more information, but there isn’t a hearing, as there is with a court case.

Once the FOS has made its decision it will write to you and the company with details of the ‘award’.

If the award is in your favour (they agree with your complaint), this letter will include details of what the company must do to put things right.