NSW Refund for vehicle purchase

[Dumbfounded]

I advertised a Motorhome for sale which after a week of discussion via text the buyer came to look at the vehicle, took it for a test drive and negotiated a price. He left asked for our bank account details to pay the negotiated amount into and a copy of the rego papers to check with REVS . The agreement was that he would pay for the vehicle and we would deliver and sign over rego etc the next day. The buyer paid the agreed amount in full later that day then messaged asking for the money back saying he could no longer take the vehicle.
Can I hold him to the sale if the vehicle hasn’t been delivered
What are my rights as a seller