Bad appraisal

I'm a seller in Arizona. We accepted an offer from a VA buyer on the 19th of January. Everything went smoothly except when the appraisal (that we paid for) came back $4000 less than the agreed price. We are not reducing our price. The buyer has no money for the difference.
The buyer and his agent have come to find out, the comps used by the VA appointed appraiser were on 2 BR homes, not 3 like ours and were from a year ago. They are now taking it up with the VA office in California which we were told would take up to 20 days. We have already been waiting for 2 weeks since the appraisal was done. The appraiser here already said she wasn't changing her figures.
Has there been a breach of contract? Isn't time of the essence? Can we cancel and not get sued?

[HomeGuru]

You must wait until the appraisal issue is cleared up. This problem is not the fault of either you or the Buyer.
The appraiser is an idiot. In only rare cirumstances if there are no similar comps, an appraiser is allowed to use outdated and disimilar comps but huge adjustments would have to be made.

Thank you for your answer. Our biggest concern is if 20 days from now pass, we will lose the house we are building and a backup contract that is better than the one being disputed. We are sleepless at night over this and are very angry. Can't we set a deadline? There has to be a way out of this!

[HomeGuru]

Read your contract for termination provisions and talk to your real estate agent or attorney.