I purchased a NetGear router/ modem and recently purchased a wireless plan.  Due to the restrictions, I am attempting my own service set-up between xfinity and my router/modem. When I attempt to activate using the xfinity.com/activate link, it takes me through the screens to link and once I request it, I receive a screen with this message:

Sorry, That Didn't Go As Planned

We are having trouble activating your service. Please give us a call at 1-800-xfinity.

Not being able to get through to a customer service agent to discuss this, I am looking to answer the question:

My router comes with both a serial number and a MAC address.  The number listed attached to my xfinity account is the Modem router MAC address.  Should this instead be the listed serial number? I ask because xfinity does not seem to recognize or connect to my device.

Thanks.