Buyer no longer wants the house

What does the contract say. You are holding the deed I would assume. How far into the contract?

As noted, read the contract. It will specify what happens if the buyer defaults.

Generally land sales contracts are written such that if the buyer defaults, they forfeit all monies paid and the contract reverts to a rental lease. If the buyer stops paying you will probably have to send them written notice that they are in default and that they must continue to pay rental or vacate the property.

If you can give us more info about where the property is located (general locales) and the terms of the contract we can advise further.

For me, this is when I jump for joy, since I made most of my money, re-selling the same house several times.

If done properly, ( I hope you did) you held the deed, and the contract was not even filed at courthouse.. You had them give a large down payment,
So when they walk away, you have made the large down payment, and just clean the house and re-sell.

If of course you did not get a large down payment, the worst (if paper work done right) it works out like renting the house, and you made enough to cover costs. (hopefully)

While I do not have any firm stats. I have two uncles, and two sons and several friends that all sell houses on contract for deeds. About 20 percent actually pay for the house, 80 percent default and move out, and the house is re-sold.