If you feel a person is disconnecting and opening up an engine, you should contact help and support. As far as calling them out on it "in a way they can't ignore" you really can't because if you could do such a thing, then people that like to herass others in chat would become a real issue.
By the way, i just looked at your live chess. Most of the games you lost were a result of you hanging pieces or walking in to a tactic (a fork, pin, etc.) You don't need to be a grandmaster to capitalize on such mistakes.