OP if you have changed the password then possibilities are the scammer can no longer access your account unless S/he has access to your email. Since you don't what you account to be accessible anymore and the option of deleting your account isn't available then maybe writing to members of
Cryptios might solve your case as they have the ability to
Cryptios:
-Main purpose is to investigate and accomplish account recoveries.
-They also have the ability to Lock accounts, if they believe it to be compromised.
Another risky solution is intentionally commiting plagiarism so your account will get banned rendering it useless but you should know you'll lose the ability to use the forum in the future so unless you intend leaving the forum for good don't used the option. (Not recommended but it'll do)