Buyer trying to pull one on me - wholesale deal

[Jeffery Neal]

So I have a buyer for a wholesale deal who is trying to pull fast one on me. 

I have two great wholesale deals that I was selling at the same time. I told the buyers that were interested that I would be willing to take 10k total off both properties if they were interested in both. One buyer agrees, we get both houses under contract for 5k each under my offering price. House A had multiple offers over asking. I started house B off too high  hence the reason I was willing to take 10 K less.  He wanted a full inspection rider but I refused and settled for a clause that stated he could inspect the sewer lateral lines. Long story short he backs out of the house B (the one that I could take 10k less on) because it doesn’t work for us” after the inspection contingency date and is now trying to force me to sell him property A for 8k less than I had other offers. He took 9 days to tell me he didn’t want the other house which leaves me 13 days with a holiday weekend to get the other one under contract. I sent him mutual releases this morning. He signed the one he didn’t want and is refusing to sign the other. 

My question is.... What are my options to walk away from this buyer since he fundamentally changed our deal and sell it to the person who was interested in only Property A for 8k more. 

The only thing I can think of is. 

A) walk away from the deal with my seller. (Don’t want to do)

B) Change the closing date for the first contract with my seller to be a day later so that I legally don’t own the house before the other contract closing date expires.  

Thoughts? Advice?