Sounds like the buyer is jerking you off.
I sold a 38 Baja to a guy in the Ukraine two years ago. I had all the money, the boat, and no contract. He just trusted I would do the right thing.
I contacted him two months later and he said the boat was stuck in customs in Germany because of the trailer not having a title. He missed the whole summer.
I never talked to him again because I was afraid of what he might say
I am sure he was happy once he received the rig.