Its best to change the name, that only costs a few $, that will give you the best new start.
He can change names 100 times. But his way of doing business is just swearing, slandering, abusive approach. You can't change that. And at some point he will fall again in this hole with different user name.
Yes this is all true, there is me hoping a fresh name will lead to a fresh start and we see someone make a good business from a very silly start.