Landline drops call after 30 minutes

We've had our landline phone with Xfinity for about 7 years and the problem with dropped calls started about 6 months ago. We didn't change anything; the problem just came out of nowhere.  We haven't had any issues with our internet; just the voice service.  For your information, we have voice, internet, cable TV and cell with Xfinity.  When researching this issue on the internet, I noticed that others have had this same difficulty dating back to 2020.  If you Google search "Dropped calls with Xfinity after 30 minutes", you will see the previous posts.  We called Xfinity for help but the service technician that came to our condo didn't know that this issue existed and couldn't fix it.  He nevertheless checked all the wires including the cable coming into the condo, the internal phone jacks and the wires connected to the modem and couldn't find anything amiss.  I will try your link to troubleshoot voice but I am not optimistic.  Modern technology baffles me.  By now, I would think that Xfinity would have a fix.  Please push this question up your chain of command; maybe someone higher up will get something done.  

user_2ng0fj thank you for sharing that additional information related to your landline. I would like to take a look into things on our end to see if there is anything we can uncover related to this issue. Please send us a direct message with your full name and complete service address to get started.

Here's the detailed steps to direct message us:
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• Click the "New message" (pencil and paper) icon
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• Type your message in the text area near the bottom of the window
• Press Enter to send your message. 
 

Following your instructions, I sent the requested information in a "Direct Message" to Xfinity Support.