Hi - my name is XXXXX XXXXX I'm a Real Estate
litigation attorney. Thanks for your question.
Unfortunately, if you agreed to the sale and to paying the $12000 at closing, the buyer can sue you for breach of contract and even for specific performance, which will require you to perform your obligations under the contract.
Thus, there is legal exposure to you for failing to fulfill the contract. If the buyer were to sue, it could seek damages
for the money or expenses incurred, and also for any other money or loss that the buyer incurred.
In a situation like this, you are really better off working out a way to pay this obligation instead of breaching the agreement and being sued.
I can understand that this is a difficult situation, but if you agreed to pay this money, you can be legally held to that promise.