The contract you signed early on ("purchase agreement") will control what, if any damages you can obtain from a breach of contract by the purchaser. The purchase agreement is a contract and terms are subject to both the drafter's point of view and subsequent negotiation. I use a buyer's agreement or a seller's agreement depending on who my client is. You need to look closely at that purchase agreement (PA) since it governs your options.
It appears from your post that the purchasers refuse to go through with the sale because they cannot come up with the cash due at closing. In addition you have invested a significant amount of money in repairs in order for this sale to go through. In many cases if the purchaser defaults (refuses to go through with the sale for a reason not covered in the contract), the seller is allowed to keep the earnest money deposit and may also have the right to sue for "specific performance" (to force the purchaser to go through with the deal) or even for monetary damages. You need to read the PA and see what contingencies allow the purchasers to get out of the agreement. For example, most PA's let the purchasers out of the agreement and allow them to get their deposit back if they are turned down for a mortgage.
Unless there is a specific clause or addendum to the purchase agreement allowing you to recover for them, expenses for the repairs you made may not be compensable. The repairs increased the value of the house and you can get a higher selling price than without them. You agreed in the PA that your home had a certain value with the repairs being made. When the purchaser defaults and you can't subsequently sell the house to a third party for the price you and the purchaser agreed upon, you may have a cause of action against the purchaser for the difference unless you limited your damages in the PA. Of course, if the purchasers can't come up with $2000 for closing costs, how collectable are they and what will it cost you to litigate?
I would recommend that if you read the PA and it appears that the purchasers have breached the agreement, you contact a real estate attorney who can advise you on the law in your state, whether you have a cause of action, chances for success, and potential costs and time frame. Sometimes a letter from an attorney can scare defaulting purchasers into performing.
Good luck.
