Replacement modem XG1v4

I am concerned about the same thing - this box's technology is a half-decade old while Xfinity upgrades its systems regularly.  I manage my elderly sister's Xfinity account from 1,500 miles away and she's disabled. She cannot run back and forth to an Xfinity store or troubleshoot these technical issues on her own.  Xfinity sent her faulty internet equipment twice [Edited: "All Caps"], but I thought it was her inability to hook them up.  Finally, a tech was sent out after 3 months and he spent 2 hours troubleshooting the 2nd shipment and had to replace that one with help from the office. Two[Edited: "All Caps"] faulty WiFi modems shipped in succession by Xfinity. FOUR months' payments without cable internet. Now her senior community has ended their bulk cable TV account agreement with Xfinity and dumped her (actually, me) into unproductive hours long chats and phone calls that resulted in several mischarges, overcharges, and never-ending instability.  I have spent hours (more like days) getting her plan documented according to several conflicting exchanges with several Xfinity reps before  discovering that her old cable box does not accommodate all features of her new plan.  More chats and conversations before finally confirming an X1 technology cable TV box from Xfinity that goes with her new plan would be shipped (again, she cannot run back and forth to an Xfinity store). Aside from the fact that the return label wasn't enclosed as promised, now I discover that she was sent this xg2v2-p box which seems to be universally problematic, at least according to comments on this forum and elsewhere - not to mention that its technology is a half-decade old.  Her son (who lives 100 miles away) plans to try to hook up the thing on Mother's day, but, obviously, that would mean he'd end up having to cancel Mother's Day dinner because, according to many posts here over the last five years, the xg2v2-p box apparently takes ten minutes to change channels.  With all of the online complaining about this box - and Xfinity in general, what is an elderly disabled person with marginal cognition to do?  I'm primed for an FTC complaint because she's been paying for features in her plan that don't work with her old box despite Xfinity reps' repeated reassurances. Add the missing return shipping label for the old box ($12/mo) and the new almost certainly old xg2v2-p box if any of the last few years of this forum's discussions are to be believed, I feel I may have no alternative but to prepare to resolve the situation with the intervention of a federal agency.  Cable TV should not be this difficult - or misrepresented. What would you suggest we do?  Thanks.