They’re all seemingly very strict about using their gear. They all are, they always are. They’re lying when they say that things aren’t compatible or something.
The biggest lie is that you can’t. You can, and most of the time, unless it’s creating a problem, they couldn’t give a shit less if their equipment is working correctly; as long as you pay your bill, and don’t complain, they don’t give a shit. They have your money, whether things work correctly isn’t their primary concern.