Yikes that sounds really bad if the colony is in the house. But don't worry, roach extermination can be really effective. Sounds like the landlord is a scumbag, but as long as the exterminator is legit and not like, the landlord's cousin, you should expect things to get temporarily better. Make sure the exterminator is doing long-term remediation and not just a kill job (e.g. traps around the property). You'll also want to keep traps of your own around to poison any roaches that try to return, get a trashcan with a lid on it, and keep your kitchen and dining areas clean, just to make sure the situation doesn't get out of hand again. Good luck with the landlord :-\