Alright, Let me explain...[stuff]... Why the heck he didn't just put a suzuki motor in it baffles me he couldn't have saved that much money.
First off, I hope this experience doesn't turn you off the idea of finding & purchasing a nice used SV. They really are nifty motorcycles (when they haven't been butchered & had weird motors transplanted into them).

It baffles me as well... he must have got his hands on the Hyosung motor dirt cheap, then rigged it in for almost nothing.
Second, as I orginally stated, ultimately it
still comes down to
"Buyer beware". Yes, it seems this person tried to defraud you.
Yes, it appears he was acting in a deceptive manner.
Yes, he's a bad man & will probably go to Hell for it.
But it STILL falls on the buyer to take proper steps to protect themselves from bad people like this. I'm a firm believer in never buying a 'pig in a poke'... I would
never purchase a motorcycle sight unseen, nor make a promise to buy it without inspecting it firsthand. If this means taking it to an expert, trained mechanic, or shop, so be it.
Finally, I hope you successfully back out of this deal with your wallet fully intact. If so, consider yourself lucky, then get back to finding a good used SV.

We have a great community here, so if you need assistance looking at a bike, etc. post up & let us know. Folks around here are more than willing to step up & help a fellow member out.
Good luck!