Verizon Yahoo problems

I have Verizon DSL and am experiencing connection problems. It seems that if I am not signed in to Yahoo messenger I cannot connect to the internet. I keep getting a message saying that a USB phone is now connected and then I can access the internet. When I get a message saying that a USB phone is no longer connected I can no longer connect to the internet. I tried Verizon support and they just passed me from person to person until I got tired of listening to their nonsense. I tried to figure out what settings are needed for Yahoo messenger but no luck. Any help would be greatly appreciated.