Buying a house problem - seller still listing

[Tom Arttus]

All,

Thanks for taking the time to read. I have a unique situation, at least unique for me, and am looking for advise.

I have a house I'm in the process of buying. I have a signed offer letter, financing approved,  I paid for and have appraisal back; all good there. The seller reached out to me after the appraisal and said he wants an additional $30K over our current deal. I said no thanks, I'll pass at that price. This week the seller listed the house on Craigslist for $30K over our current sale price. When I questioned him he said we're still proceeding with our deal as is. Today I see he refreshed his listing on Craigslist. Now I'm not sure what I should do. The current offer is in place and stands as is for about 50 days still before the original offer letter expires.

My question, can he sell if he finds another bidder? Do I lose my appraisal money? Should I approach the seller and ask him to take down the listing? 

I'm not sure what my next steps should be and feel kind of dumbfounded that I'm in this position.