I can’t tell you how many times I have had clients ask me how they can enforce something the seller said that they would do. Ultimately, if the seller refuses, it is much more difficult to enforce a verbal agreement. My best advice? Get it in writing. If the agreement clearly states what has to be done, or what has to be left, and the seller doesn’t, then you have a very clear right to be compensated. If you don’t write it down, it is much more difficult to rely on later.