Wifi extender wcb6200q stopped working when I upgraded to gigabytes

Okay here's my situation I was on the preferred 15 0 panoramic plan and recently switched to the gigabyte panoramic modem and I had a Wi-Fi extender in my guest home that had a cable wire hardwired to it to receive Wi-Fi out there. And the extender has stopped working Cox doesn't supply them anymore and they also say the pods that they do provide won't work cuz of the distance what do I do??????