Okay, I deal with the aftermath of this mistake a lot at my workplace, so I'm going to go ahead and educate everyone. If you know someone who's thinking of changing their phone service, please give them this information.
DSL Internet service is cheap because it uses your pre-existing phone line. It dumps your high-speed Internet connection onto your telephone number, and a box at your house separates the two signals, thusly:
VoIP is cheap because it uses your pre-existing Internet connection. It redirects your phone calls to a computer, and a box at your house separates the phone service from your Internet connection to that computer, thusly:
If you have a DSL connection to the Internet, and you switch to a VoIP phone connection, the phone number that is delivering your Internet service gets redirected to a computer, with which you are expected to communicate.
Thus, you're trying to get your phone through your internet and your internet through your phone. It doesn't work, and you're going to have to either get another phone line, or some other form of high speed Internet service.
We didn't cut you off. You cut yourself off.