I don't think you can "call GMs" You can only report stuff and the GMs contact you if needed.
Reporting RMTs aren't really necessary to contact GMs. Just report them. Personally I just block them, it's not like the RMTs are hiding so SE should know about them and should shut down their accounts at some point.
The cheating is another story. If you submit a complaint then the GMs should get in touch with you if needed.