Good question. Assuming that the buyer has a selling agent representing him or her, I would e mail the selling agent requesting that the cancellation of escrow instructions be signed and dated by the buyer and returned to you in 24 hours since it appears that the buyer has no intent on cancelling. If the buyer has no intent on cancelling the escrow, then you should discuss with your client about forcing close of escrow with the buyer.In the interim, you and your seller client should consult with a real estate attorney to resolve this impasse on the sale with the buyer.