AT&T DSL and Vonage

I decided to used Vonage phone service but keep my AT&T internet service but even since I change to vonage I keep losing my internet this was not a problem before vonage, vonage was more in my budget but I wish they would stop turning off my internet because I don't have there phone service this can be very sicking. I have has them out to my home a few time and still the same thing but they was no problem with the service until I decided to used vonage