Xfinity won’t redeem WiFi extender it advertised

Xfinity won’t redeem the pod for our router. We have called twice, we’re told to pick it up in store. Two stores told us we can’t do that. We tried to call again to redeem the pod, we were kept on the phone for over an hour, placed on hold for long periods of time, told our router isn’t compatible, told to purchase an after market extender, and no solution to be had. We took the router to the Xfinity store, we were told it’s compatible. Our internet won’t reach 4 rooms in our home. Why can’t we redeem this pod?