If the down payment goes to an escrow account that you don't have control this sounds like an incomplete sales. You should wait until you collect funds to report the sale. It is possible that there is a complete sale if you are agreeing to receive some money now and some money later. This would be reported as an installment sale on your taxes. You calculate the gain including all proceeds of the sale and then only recognize the percentage you received this year. In future years you recognize the percentage collected.
There is also the home sale exclusion to take into account. It is possible that if the exclusion excludes the entire gain that you report nothing on your return for any of the years.
