Is there such a form as "cancellation of contract for deed" in the state of Texas?

I entered into a contract for deed and the buyer has failed to make payments for three months and then just called to tell me that he no longer wanted the property. I sent him a notice of default by certified mail and served a copy on him in person. I was told by the clerk at the courthouse house that filing the notice was not enough that I needed a form mentioned above. I have searched and not been able to find one. I called several real estate lawyers and no one has returned my call!