If you don't get anywhere with the company, or just don't feel like talking them, you complain to your bank. I had to do this recently. It took all of 3 minutes to get my money back with no questions asked other than "did you authorise it?" and to get a block put on my account to stop that company ever taking money again.

This costs the company money and a lot of paperwork, so the threat of doing it is often enough to get them to sort themselves out.