They don't want you to use their platform, what's the problem, mate?
Why do you keep signing up onto it with alternate accounts if you are not wanted there? Is it the only gambling platform available?
I think they have a right to terminate their service with you as per the terms of service and you should respect their decision too.
However, at least the casino management must provide reasons or clarity for the problem. Every casino site must be able to properly solve the problems experienced by its users.
However, this can affect the reputation of a casino, so that there is no gambler who is disappointed with casino decisions without definite clarity so that gamblers can act as they please because it can damage good reputation and make other gamblers distrust the casino site.
I think also giving a reason or clarity is not a difficult thing for casino managers.