I don't think you were rightfully banned then because I also use TotalRP3 and I have not been banned for it at all. Definitely should put a ticket in or a call to Blizzard because it sounds like you were one of the few wrongfully banned.
TRP3 is an addon that Blizzard themselves actually work with... not on of course but they did work with the creator recently to check on people who abuse the addon for malicious conduct.