Sal,
No, don't ban him.
He is providing a public service, he is alerting people to the need to have proper business dealings. He thought he was agreeved and brought it to this forum. His lack of due diligence (and lack of funds) in the deal and in using this forum (a little surfing of this site would have told him this was NOT the place to yell "FIRE!!!") to attempt revenge has been an instructional help to all our members. To say nothing of entertainment!
He is attempting to verbably joust with Jamo, a master of the rapier, using a broomstick. The results are not in doubt.
The quote "it is better to remain silent and be thought a fool, than to open your mouth and remove all doubt" has never applied more than here. Let him keep hoisting himself................