Charter Communication Failed to Provide Basic Services Pasadena California

In October I asked Charter Communications to install a cable package with Internet. They used heavy sales tactics to entice me to also use their VOIP phone service but I was already happt with Vonage. Since installation, every time I try to use my phone while on-line my entire Internet system crashes. Charter has tried to fic the problem three times and their only solution seems to be that I cancel Vonage and switch to their service.

This all seems very suspicious to me.

Sterilecheck
Eagle Rock, California
U.S.A.