If the digital receiver you purchased on E-Bay was originally a Comcast Digital Receiver, then they may refuse to activate it (as it should have never been sold in the first place), or they may simply start charging you a rental fee.
If the digital receiver you purchased on E-Bay was NOT originally a Comcast Digital Receiver, but it meets their required specifications (don't ask), then they *may* activate it for you. They *may* charge you a fee for activation, but in my case (for my Internet Cable Modem), they did not.
-Wolf sends