I requested a doctor's letter (diagnosis confirmation). I had to pay for it before I see it, but I opened at the counter and it turns out it contains mistakes. It looks like they typed my information into another patient's letter, and forgot to edit properly. I said I'm not paying for it, and requested my money back. They said they can't do that - they can ask the doctor to rectify the mistakes, but they can't pay me back. Can they actually do that and keep my money just like that?