Can buyers back out a last minue-due to wanting a better deal--contract signed --escrow papers completed-rs?

real estate offer accepted, in escrow for 25 days-all repairs completed-last minute homeowner wants a better deal-They offered us 2.435 on the contract--now they say they can afford 2.2 million--information that market is dropping 50% is what they are using to hold us & wants to negotiate. They have 60,000 in escrow-they made us loose other offers and time--do we have to give back their deposit out of escrow--very dishonest people. They never removed contingencies.