I returned my Quantum Gateway router via a return kit 3 months ago (I purchased my own unit). However, for the past 3 billing cycles I am still being charged the $10 rental fee for the router. The past 2 months, I contacted Verizon about the bill and they confirm the router return was received and issue a credit for the fee. I do not want to have to keep contacting them every month to re-explain the situation over again to get the fee removed. How do I get Verizon to stop charging me the rental fee every month?