Hi Jwdevalue, thank you for reaching out to us on the Forum. I am sorry to hear that you are leaving Xfinity Mobile, I can understand your decision. Having to pay the extra $20.00 a month per line adds up quick.
Since you are no longer with in the buyer’s remorse time frame, we do not have an option for you to return your device. When you port out your number this will cancel your service, being that your residential service is no longer active you will be charged the remaining device balance in full. You can pay partial payments to the device prior to cancelation to bring the cost down and prevent being charged a huge amount once you port out.
Here is a support article with information on what happens when you cancel all services and have a device payment plan.
I hope this information helps. Please feel free to reach out if you have any other questions.