IF (big if!) there is competition in your area . . . show the one what the other can do, and explain why you prefer one over the other.

See if you can sign up for a free trial of the competition's service (I had two ISP's at the same time.--cable and DSL)

Take screenshots of the Tools->Statistics->Bandwidth->Download graph while downloading from a reliable site (I use the free and legal content from magnetmix.com/audio2.shtml )

Do this for both ISP.

Email the screenshots from both ISP's to the help desk, and ask if they can repeat the problem. See what they say, then show them why the competition is better.

If they don't help, go to the competition. The cable help desk guys helped, and made the techies stop filtering my bandwidth, so I stayed with the cableco.

Once the ISPs know you already have the competition installed and you have a month or so to decidewhich one to cancel, they can be quite cooperative.