Dropped calls

My calle are dropped at the 30 miniute mark. Eather outgoing or incoming it does not matter. Tride calling xfinity same old story. Reset the modum,send a refresh to the modum. Then its maybe your phones are not conected corecttley. I acutuly bought new phones thinking because mine were around eight years old. Did not change a thing. Even made a appointment but no one showed up and aparently it was never made by the agent after giving me a date and time.

Any one else have this problem. I have new Panasonic phones 2020 model