Backing out of a deal -Sheriff sale transfer

[Fahima Hilal]

My client had been in contract with a seller who had won an auction bid at a sheriff's sale. 

Half-way through the AR period, he raised the price by 4K stating that due to holding costs with the sheriff, blah-blah .My client agreed and was scheduled to close. Seller then calls him and says there are tax liens that have come up on the property and he wants him to split the difference .My client does not want to proceed with the deal anymore and asked for a cancellation. Seller is not letting go stating the contract is in force. He is willing to give it without the cost of the tax liens . But my client is no longer interested . WHat are his options considering the following:

1) He has not signed the amended contract for the extra 4K seller wanted 

2) I have the text messages from the seller stating that the deal is off since buyer is not willing to split tax liens 

3) He has already put in an offer for another property