Blizzard do not restrict the game, you either can play or you can’t. There are reports in the classic forums of people having problems with mail and the AH, personally I think it’s addons.
I have checked a bit further and did you get an email from Blizzard saying they have restricted your account? Check your spam folder.
https://eu.forums.blizzard.com/en/wow/t/that-action-is-currently-restricted/505510/17