Your account has been terminated due to Theft / Buying gold

Greetings dear players. I faced such a problem. I play on this server for a long time (since 2017). It would seem, nothing like that. I play almost every day. I say right away, I didn't violate any manipulations with the game's policy. A couple of days ago, I came home from work and decided to go to the game. Log in, writes that your account is no longer valid. I go to the site, there is a ban with a comment (theft or purchase of gold). I sit in a daze. I've never seen anything like this in my entire game on this server. Can mistake what? I wrote to the ticket, waiting for the second day of the response. Who has faced a similar situation? Thank you in advance.

P.S.
I apologize for any errors in my text. I'm from Russia. Unfortunately, I don't know English very well. I hope that Google translator will correctly convey my message to you. Thanks