whalemixer1 haven't been active for more than 4 days (before you posted this). I hope they will resolve your issue as they did with op when they log in.
In the meantime, I suggest you create your own scam accusation thread and provide enough evidences to support your claims.

This honestly doesn't make any sense. The letter of guarantee is nothing else but a signed message. It can be a .txt file. In any case, you have to provide it and let the customer decide whether he wants to download it or not.