the thing is hes only placed himself in the situation to get fucked, from what hes telling u. u have no obligation to him. he tried to handle it his way, and u legally have ur own right to handle it the way u want (meaning not killing him or hurting him, lol). he decided to pay for something, just explain that u'd like to see a receipt (Which u are lawfully owed) or proof of the costs, and then u'll pay him. fuck it, even say that the moneys not the problem, but u know it didnt cost that much. u have this to ur adavantage. having her info means nothing.
BOTTOM LINE: HE ONLY HAS PROOF THAT HE PAID FOR IT HIMSELF. so what, that means nothing. u can say "hey, he said it was fine, he was gonna handle it himself."