DPC3941T router with intermittent problems

Internet has been intermittently dropping out as well but is working for the moment (it dropped out again this morning for a short while).  I tried calling the outage number via cell phone (also through Xfinity), but the chat bot can't handle intermittent problem reporting and hung up on me.  Voice service cut out again when I got to a live agent (finally and with great difficulty).  She called back and it cut out again in the middle of her call.   She agreed the modem probably needs to be swapped out, but as she was about to give me one of two choices, it cut out again.  Looks like I am stuck driving an hour to the nearest store to wait in line to get problem resolution.

The live agent called back again.   Recommends  an XV6 modem to replace the DPC3941T that I am currently paying monthly rent on to Xfinity.  The choices are she can ship me a replacement modem and that will cost me money to do that.  Or I can pick one up at any Xfinity store and there is no charge for that.  I am trying to understand why I am paying monthly rent as part of my bill on a modem from Xfinity but would be charged for having a replacement shipped to me when the agent agrees this was an old modem that needed replacement.

The voice service kept cutting in and out during my conversation with the Xfinity agent.  I mentioned going back to my hard-wired landline carrier so that I don't have a single point of failure (Xfinity service).  I was offered a free phone from Xfinity hooked up to the old land line but declined that as all the drops in my rural area are overhead, no underground cables like the old landline service.  Last winter during an ice storm, even the cellular did not work and I had no means of calling 911 if needed.

Hey there, @MarmotObserver! Thank you so much for taking the time to reach out to us here on the Xfinity Forums. I am very sorry to hear about the experience with the modem, it certainly is not what we want for our customers. I appreciate you sharing what you have done with troubleshooting, and reaching out. We would be happy to look into the account further with you. Can you please send us a DM to get started?

Please send us a DM with your full name and address to Xfinity Support.
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I have responded in Direct Messaging

That may be, though I think I have discovered what is knocking the router offline and disrupting service intermittently.  Going through the call logs it shows calls I have never placed myself going to 202-813-1600.  That appears, from what I can tell) to be the NOMOROBO number Xfinity uses.  I believe Xfinity has been upgrading its NOMOROBO service recently.

https://www.reportedcalls.com/2028131600

https://nomorobo.zendesk.com/hc/en-us/articles/205762195-Comcast-Xfinity