Last free bump.

No one including him (from what I can see) said you scammed him and so he was customer from hell  .... so what?  He didn't like your product or how it worked.  Shit happens. Had you simply only done what you did (refund him which was the right thing) and walked away you wouldn't have generated all these messages.  Obviously you have never worked face to face with people in sales or you wouldn't make it to day 2.  LOL  Good luck!