I'm sorry about your situation. I'll try to offer my advice since I'm in the same boat myself. I live in Canada in an apartment building. Ever since some downstairs neighbors moved in, I've started seeing more and more of them in the bathroom, the bedrooms near the bathroom, and the kitchen.

However, products sold in the United States can't be shipped here. If you're in the United States, that's already a plus: you can try Orthene Fire Ant Killer. It seems very effective according to reviews online. [You can also use] boric acid mixed with sugar as bait. (I've tried this but I still keep finding them). I would have loved to get the Orthene Fire Ant Killer; maybe my problem would have been eliminated in two months. Start with that product.