XFi pods won’t stay connected

In the last month I have had nothing but trouble with internet speeds and losing connections there have been 10 or more tech guys here and they can’t find the trouble I have 6 pods I can reset my modem to factory settings and everything will work for a couple days pods as well then I go to the xFi app a couple days later and pods are off line and xFi app shows that there is nothing connected to internet when in fact everything is connected except the pods please help