Simple problem with simple fix, but can't reach anyone who will actually *do* ANYTHING!

All I need is for one person to take responsibility for a billing error and correct my monthly rate. That's... literally it. A single competent individual can solve my issue in no time at all. My wife had the exact same problem with her own account this month, called in, and got it fixed on her first call in under 6 minutes including hold time. As to why I've now spent over 4 hours and 3 contact attempts trying to do the same thing, with zero results, your guess is as good as mine.

In the last two weeks, I've spoken with THREE separate agents; after explaining the problem in excruciating detail each time (which I shouldn't have had to do even once), every one of them eventually figured it out and said along the lines of, "Ok, yep, that's definitely a mistake. Sure, we can totally fix that - I just can't do it myself, so I need to (have somebody get back to you/need you to call another number/etc)." So I do what they ask me to do. And then, of course, the next person I speak to—who's supposed to fix the problem—just says the exact same thing and passes the buck on to the next agent who then—you guessed it!—does the same thing AGAIN.

Final straw was spending 2 HOURS on hold last week opening a ticket to request a call back from a supervisor... only to have nobody ever even attempt to call me back, and now apparently the ticket is automatically closed.

What do I need to do to speak to somebody who can actually HELP with anything?!