N.W.
I had the same problem. At first I used terminix, they would do a treatment and insist that I wait at least 20 days or so before I can complain if the ants aren't taken care of. I let this carry on for 3 treatments before I canceled my contract with them and demanded my money back. (not going to get into how hard it was to get my money back from them)
I ended up using a mix I found online. Half Borax (local store, with the detergents) and half powder sugar. I swept it in all the cracks between the walls and floors and the cabinets. They were gone in just a few days!
I did get them again the next year so I just did the same thing right away and we've had no problems.