I doubt that Overture checks based on the IP, more likely they go by the email address or billing address. So, if you can use an alternate email along with an alternate payment method, you should be able to sign up with them again. You could also plead ignorance with them since it sounds like an honest mistake. If you are spending any kind of money on sites not related to gambling, I can’t imagine they wouldn’t at least listen to you and probably reinstate your account if you promise not to do it again.