I see... haha... sorry mate... have you thought about creating a maximum open number of tickets in the settings? This way you may get 5 open tickets but it won't keep going for ever.
I don't know if there is much that can be done, you can consider banning the email address in osTicket or, maybe at your email host? Your host may also be able to stop out going messages to this email address by a rule or by a blacklist?