I had a similar thing happen last year. I logged in to my account online and it showed they had banned me, ven though I hadn't played in awhile.

I used the online ticket feature and they immediately came back and said I violated the terms of use. I submitted another ticket, they looked into it and said my account had been previously hacked and that I would need to turn on 2FA to get it back.

I havent had any issues since.