I got my account back today too. I'm pretty sure it was a false positive since I played at least a couple hours every day before the ban and didn't notice anything unusual. They gave a generic response of unusual activity and didn't refund me any days of lost membership, but at least I got my account back. ¯\(ツ)/¯
It's often the case that an account is compromised without the owner knowing it, and is used to gold farm on the opposite game that's being played by the owner such as yourself. This may have been what happened with you, can't tell for sure without knowing what account it was, though.