Originally Posted by DamageX

Tell them that if he charges back you'll fight the chargeback with all legal means necessary and will do your utmost to prove that HE was too stupid to handle the site and you made NO false promises whatsoever. It may drag out in time, but by the time it's done he'll have a mountain of legal fees to pay, his AND yours. Then ask him if it wouldn't be cheaper to be nice, tell you what's wrong in a nice manner and perhaps even get your assistance and/or a refund in the process.