Obsolete Cable box

I have made three appointments to have my cable box replaced because the old one no longer works due to system upgrades in my area.  All three appointments were canceled after I waited all day for the three hour appointment window.  I am near but not in the Augusta area and we were not affected badly by Helene.  Someone texted from xfinity saying I did not have a problem on my line (I guess they checked remotely).  But I can't get a live agent to explain that I still need the appointment to deliver and install the box.  I have had no service for going on three weeks now due to the upgrade and I can't get anyone to service my account.  The AI phone based customer service hangs up on me.  The online agent can't make an appointment because they are blocked from doing so.  I am paying full monthly fees for no service and can't get anyone to keep the appointments I've been able to make.