If the buyer is claiming 'wrong font' and initiates a PayPal dispute for SNAD then get him to specific exactly which font he was expecting. You have a font sample in one of your listing's photos which should have made it more than clear which font he was going to receive.  Clearly mentioning the font style would have been a good idea though.

eg If he indicated that he was expecting to receive Arial narrow and your listing clearly showed Impact then it will all come down to buyer remorse and you can make a reasonable refund offer.

( original item cost less 'hire charge', no postages costs ).

Not having a shot at you but why can't the English send a printed example of the literature they wish supplied when having stuff made in Asia.