Also, are there any way to delete old posts / topics? I want to clear my name from it.
You can try to delete the posts one by one. If you cannot delete a post then can try to edit it and put something like "." instead of the text. The last possibility is if the posts are off topic you can report them to the moderator to delete them but this is only if the posts are somehow against the rules.
I'll leave you a not on your trust wall that the account is successfully recovered.