I have had direct communications for the past 4 mo...

I have had direct communications for the past 4 months and the speed is horrible. I tried to get it of the contract, but the manager advised me that the contract states that the speed can not be guaranteed, which means I can't get out of the contract without paying the cancellation fee. Tech support started that their growth has been substantial that they can't support the speed needed and that they are working on their network. My question is, why do they continue to add customers if they can't provide the service?