He can terminate the contract and ask to be put back in the position he was before the contract. He had a domain before the contract. He will be able to claim costs and damages in addition to the domain.
I haven't seen it. I was tempted to ask for a copy. I assume that the contract is not a complex one, and that it would allow him to fall back on 'what the law implies'.
Anyway, I would be very surprised if seller asked the buyer to agree to a contract that would potentially leave seller out of domain and cash in the event of buyer default.
.... and contracts do get thrown out of court.