AC1750 keeps disconnecting frequently sometimes multiple times within hour

Hello There,

I just purchased AC1750 modem and using it with xfinitiy cable internet.

I am using it with my macbook and couple of iPhone devices.

First of all netgear doesn't even have this model on their website for product registration so was forced to use wrong product type while registration. 

My problem is this modem keep disconnecting again and again and our wifi network is completly lost. It doesn't even come up back even after waiting for hours. To make it work, I need to hard boot it everytime this problem happens which makes it again workable for timelines as per it's grace.

Please suggest what to do.