First make a GDPR request to have your data deleted.
After som grace period, register again. If they tell you that you are banned, they show that they have not deleted the data. File a complaint with data protection authorities and have them fined.
Of course the better answer is just not to do any business with shitty companies.
I do wish that software people sometimes bothered to extend a baseline level of competence to other people once in awhile, though. Like--do you think nobody thought of this situation?
The better option is likely a set of hashes of various permutations of data, though, with some set of hits prompting for further information (such as an e-mail or a full name match requiring proof of identity before allowing usage).
However if they could do something like use your credit card info to identify you and have a hash of that - until you changed bank etc.
At any rate I don't think it is impossible to beat the ban.
The more fuzzy you make it ("normalizing" the data before calcukating the hash), the more likely it will cause a false positive for legitimate users.
It's probably only a matter of time until we read articles on HN where such an algorithm got it wrong.