I actually had a manager from comcast as my own manager in a different job for a while, and he said the costumer support isn't stupid but that they are forced to appear this retarded by the higher ups.

It's really shitty but nothing the worker at the phone can do anything about, they have a protocol they need to follow or they get axed.

Your best bet is to demand someone higher up, ask for their manager and don't hang up on them, because they aren't allowed to hang up on you so they will cave eventually. Usually the manager is then able to help you.
Also I would recommend not swearing at them, it'll just make them want to actually fuck you over, something that you probably want to avoid when trying to get someone higher in the foodchain.

in all honesty, unless you live near a major city your isp is going to suck and price gouge you. There are a lot of things wrong with ISs, and one of those being they pretty much all worked together and mapped out where their monopolies were going to be, and choke out anyone else trying to start up.