The OP has a screenshot of your platform's withdrawal page, which shows his username. Are you perhaps implying that the OP is lying and the screenshot he shared has been doctored to make it look like that he has an account on your website?
OP also mentioned that after complaining in their ANN thread, he couldn’t log into his account due to incorrect credentials. Given that, and the fact that an anonbet representative confirmed they couldn’t find his username in their database, there is a possibility that they deleted his account. This is just an assumption, though!
If OP is still interested in resolving his case (he has been inactive for more than a month), he should start by providing more proof to confirm that he had an account on anonbet, such as the registration email or something like that.