Scammed by Investor San Diego

[Annie Park]

Looking for help with my situation.

I am selling my rental in San Diego and received all cash as is offer of $320,000 from investor/agent.  We signed the purchase contract 7/11/2019 and scheduled to close on 9/3/2019 when the current tenant moves out.  Escrow was opened with $1000 deposit.  I was surprised to see my rental is now listed on mls for sale $359,000 and the buyer acting as my agent. 

I feel I have been scammed. It looks like his intention was to purchase only if he found a buyer. 

Now the buyer is telling me he is not going to complete the purchase.  Contract states "PROPERTY TO BE SOLD AS-IS. ALL CASH OFFER".  No contingencies.  Can the buyer just cancel the purchase contract?  Is there anything I can do?