Tricky question. In Nevada buyer's have 5 days from receipt of HOA pk. to agree or decline transaction based on HOA rules and regs, which ostensibly happened if you accept that the date of delivery to the buyer was Dec. 18 and buyer responded by Dec. 22. The real question is whether or not the agent was unable to deliver to buyer due to circumstances beyond agent's control, i.e. buyers were out of town. I had this situation happen to me a while back and I informed the seller's agent, so we extended the time limit. If the seller refuses to refund deposit, I would suggest that you get some legal advise.