Impact pool plastering llc

I hired this contractor through Thumbtack specifically to repair a pool leak. He told me the leak was inside the pool, even though another licensed pool company had already confirmed the issue was at the pump and outside the pool. I relied on his assessment and agreed to an $8,000 repair and pebble upgrade with the understanding the pool would be repaired. After the work was completed, the pool continued to drain exactly as before. He then claimed his work only fixed ?one problem,? which was never disclosed prior to payment. I spent an additional $800 to refill the pool, $250 in water costs, and $2,500 to rehire the original company, who confirmed the pump was the issue all along. I requested a refund. He refused and has stopped responding, including to my attorney. I had a $600 problem and he got me for $8000!