I’ve turned to canceling their accounts and responding with pretty harsh messages implying the person using my address is a moron who can’t type his own address

I’ve turned to canceling their accounts and responding with pretty harsh messages implying the person using my address is a moron who can’t type his own address. It’s not very nice but a lot more successful in getting them to quit entering my address, being nice just results in some half hearted apologies while the behavior continues.