If your answer is yes, he/she should draft an extension of time addendum. If your answer is no, he/she should draft a cancellation of contract, release of deposit and joint escrow instructions.
The next step if the above scenario doesn't work out is to contact your real estate agent's broker. If he/she IS the broker, proceed to step 3.
Step 3 is to contact an attorney and let the real estate agent/broker know that you have done so. Depending upon your purchase agreement, you may have agreed to arbitration if a dispute arises. Now it's time for the attorneys to take over...your attorney, your agent/broker's attorney, the seller's attorney and the seller's agent/broker's attorney.
P.S. Here's a link if you need to look up an agent/broker - http://www2.dre.ca.gov/publicasp/pplinfo.asp
It is very common for escrow to close a little later thent he scheduled date, however, an extension should have been requested by the party needing the extension in writing. Do you know for a fact that its' the seller lingering? I would suggest you find out what's going on and then see how it effects you as trying to win on a breach of contract on real estate matters can be quite expensive and time consuming. Good luck and please feel free to call or email me anytime. You should also visit the CAR website to find out more about your legal rights. http://www.dre.ca.gov/