Re-read what I said, but this time assume I know what all the words mean, I chose them on purpose, I'm over 30, and I know at least a little bit about what I'm talking about.
T-Mobile isn't Comcast, but did you know that my state has to fine Comcast multiple times per year over persistent "mistakes" in how they organize their bill? You'd think after decades of saying, "no, that's a lie, no, that is intentionally unclear, no that is a lie, etc." that they would learn to write a clear bill. And indeed, it becomes obvious eventually that none of these are mistakes or misunderstandings.
When the person on the phone doesn't know the answer, but they claim to know it and guess, and are wrong, that isn't a misunderstanding. That is somebody telling a lie. That they know the answer is the lie.
If you look at the actual accusations and the screen shots, there are numerous examples where to defend them the best you can do is say it is a smaller lie than it appears to be. But none of that makes it into misunderstandings. They didn't misunderstand, they lied about various things while at the same time also misunderstanding the (incorrect) numbers on the screen.
That you're a fan of their service overall tells you nothing at all about if it was a lie or a misunderstanding. And if you were close to my age, you'd have seen these same things from so many companies for so long, you'd realize that the workers in that call center have been dealing with these issues for decades. The guy on the phone may be new, but his boss isn't. They do actually know what they are doing. And if you also read business news, you'd know that their industry media tells them to do these things. It is a known way of doing business, to keep the customer in the dark and feed them shit. They have formal analysis that tells them it makes them more money than providing good service. That is another reason it is not believable when they pretend to accidentally do exactly the things their industry rags tell them will make them more money. They're experts in their field, and they're doing things the way they intended. And that's why so many companies are doing it exactly the same way.