I recently had a buyer agree to purchase an on-site caravan for $8500. They agreed to pay a $4000 deposit and the remaining balance when they returned from a swing away at work on 2nd of July. I received the deposit on the 9th of June. On the 30th of June, the buyer sent a message saying they no longer wanted to buy the on-site caravan stating a change in their work situation meant they didn't want to buy it now and they asked for their $4000 deposit to be refunded. My question is, do I legally have to refund their deposit under Australian Consumer Law?