i would NOT do it, it seems like its a scam or something, they get all these iPhones, pay via check, make it bounce....., or they sell it on eBay for MORE..
I have been ripped away. I sent them my iphone and the lorri I have sent them !!!!! They sent a ticket for the post false track and are now gone. Never rely on. On their website there are positive feedback but I have cheated.