When a fumigation does not work

So I was polled online with an advert to use the Bugman for pest control. They came, they fumigated. A month or two later the roaches and fleas were still there. We then had numerous follow ups over the next few months, but they were unable to effectively fumigate the house. After the fourth attempt I got a mail saying that they cannot help me anymore as the problem is too much for them... wow. So it's my faulty for having too many ****roaches and fleas.