ROACHES ROACHES ROACHES EVERYWHERE!!!!?

I live in an apartment complex, and our building has come down with a BAD case of small german roaches over the last year. They come and exterminate VERY often, and I have tried everything possible!. We have tried bombing the house many times with different products and we have also even tried ultrasonic plug-in devices. It has gotten to a point where we keep a can of raid on stand by and keep everything clean and clear as possible. Nothing is helping! - The exterminator states the problem started on the other side of our unit upstairs. They have located the main nest in that unit and have evicted the trashy people that lived there before. The last thing that I have to say is the the exterminator is indeed, Terminex, and they have found our roaches immune to gel, bait, and boric acid.