randomly generated account information?

Was trying to create an account for MuseScore. Put in my credit card information but then it didn't ask me for any other information. Gave me a randomly generated username, email, and password. My username and email are both just "user" followed by a string of numbers. I can't change my email without knowing my password which I don't know because I never created one. And I can't change my password without knowing my email which is not even a real email. Contacted tech support but from looking at other forums I'm not feeling too hopeful that they will respond. Is there anything that I can do to fix this? Has this happened to anyone else?