This isn't a free process, so you'll want to try and get your money back by contacting the company, and then any free arbitrator or complaints scheme first.
For claims above this amount, you'll likely be places in a "fast track" or the "multi-track" system where a hearing will need to take place and legal advice is likely to be needed.Once you've started the process, the business or individual must respond. You'll be sent an email or letter with a deadline for when you can expect this.If the person or business denies owing money, or you disagree with their response, you might have to go to a court hearing.
When you make a complaint, make sure you follow this so they have the information they need to resolve the issue.The company in question then has eight weeks to come to a decision.How to take your energy supplier to the Energy Ombudsman