tor@t-3.net:
You somewhat made a mistake here - you've got to have an exit policy that (minimally) rejects ports 25 and 465, or else your relay becomes a giant abuse tool for spammers, scammers, and phishers instead of what you intended it to be (which was a standard-functioning Tor relay).
Please don't blame the victim. If this ISP acted differently than what they initially promised, then they are the problem.