Solid Rock Custom Carpentry

We're doing a major remodeling project on an 1950's home, and being old, the original builders had installed tile directly into the concrete slab. Once we removed the tile, the concrete was no longer level with the rest of the house. Given that we want to install wood flooring which requires it to be flat within 1/8th of inch, we knew it would be best to hire a professional to do the flatwork. Craig came out and gave us a bid for $600 for the job. My husband directly asked him if he was confident that he could do the job and he said that yes he was. It wasn't a very big job and Craig was able to finish the job in an evening and about half a day. He charged us another $200 and then left. It was immediately apparent that it was wavy, but we weren't expecting it be perfectly flat. However, when I got a flat board out I found large that were areas too high and areas that were up to 1/4 inch too low. We called, we emailed. He took our money, never to be heard of again. He did a horrible job, he overestimated a small job (imagine how off he would be if it was a larger job), and made no attempt to remedy his shoddy work. We have attempted to contact Craig multiple times, directly, to try to resolve the issue and have been completely ignored. I feel scammed!