Lost TV Box

I will be cancelling the TV service, but I noticed I would need to return the TV box.  I haven't used that box in probably 10 years and have no idea where it might be.  Is there any way to avoid the non-return fee?  I've been paying a monthly fee for a box for years, which more than paid for the cost of the box I'm sure.  I tried using the Xfinity chat, but the person I was chatting with didn't understand what I was asking for.