Bedbugs on my apartment?

I live in Los Angeles I currently moved in to building a couple months ago I noticed my 1yr old baby had a lot of mosquito looking bites all over his body then I started noticing them on mine too they're really itchy.. My husband picked up the matress and it was full of bedbugs so we cleaned up threw the matresses away and bought some new ones. I let the manager kno about the bedbugs so she sent some one in to clean up the bugs on my unit .. It didn't work, so far I've had the manager bring some one in 4 times in the past 3/4 months .. Whatever they're doing isn't killing this nasty bugs ..can I sue the landlord for not killing them.. ? Shouldn't they fumigate the hole building?