Canceling phone service will not affect your Fios internet. Since fios internet doesnt require a phone line, its not a required service.
The only thing that may be an issue is that I'm told that if you do not have a Land line phone, you must change your billing to an automatic billing on a credit card. They will not send you a bill in the mail unless you have home phone. At least thats what they told me. But since I wanted a landline just for times when the cell wasnt working anyway it was not an issue for me but I've heard others that didnt like having to have it billed to a cc. But as far as I know, thats the only change/drawback to having fios without a phone.
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