Hello,
For three years, we've had Verizon Fios Internet and TV. We've never had a phone.
Today, the contraption Verizon plugged in the wall (sadly, I'm not really sure what it is, and had forgotten it existed until today as it's tucked behind some furniture) started beeping and the replace battery indicator light is on. Furthermore, when I turn on TV, I am greeted with this message:

My questions are:
(1) If I don't have phone service, why would I even have a battery backup (much less need to replace it) to allow phone service during power outages?
(2) Since I have only internet and TV, can I safely go without replacing this battery?
(3) If the answer to #2 is yes, then how do I get the thing in the wall to stop beeping every 30 minutes?
Thank you in advance to any responses.