Asking to amend contract

[Shawn C.]

I have a buyer and agent that I’m under contract with to purchase my home. We came to an agreement after some haggle and are under contract with a contingency on the sell of their home. They keep asking me to change the contingency date as they’re not getting offers on their house. Now they got an offer and want me to change it again because their buyers can’t close quickly. I’m frankly tired of dealing with them. They don’t want to pay more even though I’m paying taxes and interest while they casually market their home.

Since they’re asking me to change the terms after it’s effective, can I just void the contract? Someone told me if they try to renegotiate after it’s effective, and I don’t want to negotiate, I can void it.