I'm questioning the competency of the ISP for several reasons. 1) They should be clear in communicating about whatever they view as abuse. Just telling you to "stop" without explanation is unprofessional at best. 2) This doesn't even look like abuse worth reporting (i.e., "welcome to the Internet"). 3) They sent you non-redacted logs containing what looks like browsing history of other customers? Wow.
I would personally just explain you are running a Tor relay. If they object, that's within their right really, but it might be time to find a new ISP in any case.