How much money to sign a release of sale and cancelation document

[Luis Fernando Rojas]

I have a very rare case, at the time of closing the seller decides not to close and cancel the sale, obviously he couldn't because we are under contract and I told him that we would take legal action to make the closing, to which he tells me "How much money would it take to get you, as the buyer, to sign a release of sale and cancelation document?". I have not heard of a similar case and I don't know how to handle it, should I continue to force the closing or should I request the money, and in that case, how much should I request?