Internet drops when a phone call comes in

[#1]

When we are all online, and a call comes through , even if we do not answer it, we all go off line, until the phone stops ringing or until the call is answered and then when it ends. Why is this happeneing? This used to be an issue when we had DIAL UP service, but we do not have that now. ? I have mentioned this to Verizon before, but they just tell me it should not be happening. And then of course they try to set me up with more services...etc. I sort of feel that because it is not supposed to be happening that they do not believe it ! 

[#2]

What kind of internet service do you have?

[#3]

If you are using Fios internet the phone has nothing to do with the internet unless you have VDSL.VDSL is mostly used in apartment buildings. If that is the case you need to have VDSL filters on every phone in the house or a VSDL splitter were the wires first enter the home otherwise it will knock out the modem everytime you get a call.