Just want to reiterate the most important point I made because I want to make sure it sinks in.

The cancellation agreement is far more important to the seller than you. They cant make you buy the house but the seller cant sell the house unless you sign cancellation papers. If you walk away eventually the seller and their agent will have to find you.

If you wrote a check stop payment on it. If it’s in escrow, just contact escrow directly to cancel.