Need technician for repeated T3 timeouts / intermittent internet drops

Since late August I've been experiencing multiple daily, frequent, drops in internet from a few seconds to a few minutes. They're never long enough to be categorized as "outages" by Xfinity, but I work from home and it's led to serious disruptions during meetings and presentations. 
 
I'm now using an ethernet cord to connect to the router am still having the same issues. I've tried all the standard fixes  - restarted my modem, checked the cord connections and (now) an ethernet cord to connect directly to my laptop.

The issue is intermittent and occurs multiple times per day. I'm not asking for a point-in-time connectivity test. My modem's historical DOCSIS log shows repeated critical T3 ranging failures and MDD timeouts, and the downstream channel diagnostics show very high uncorrectable errors. I need a technician to test the coax/drop and RF signal.

When I've tried to schedule an appointment with a technician, support claims it's likely a modem issue. I'm confident this is not the case.  Secondary, but I'm also interested in options for reimbursement of monthly costs due to the frequent drops and disruptions.

Help/support would be appreciated as Xfinity's chatbots and phone support has not resolved this issue.