Been with BT for years; had a few issues to start with, because I was using a Mac, and it kept dropping out, Customer Service was a bit flakey because their help desks had been outsourced to India, and they really didn’t understand Macs. Eventually I managed to get put through to a Mac literate engineer, and we spent at least an hour trying to sort the issue, with no luck.
Until I was keying in the router password for the umpteenth time, and I was reading the characters out loud as I tapped them in, and he stopped me, and asked if I’d put a hash symbol before the password. I hadn’t because there was nothing in the literature to say I needed to. Apparently BT required it, but didn’t bother to tell anyone!
Once that was established I had no further issues, and they dropped it a while later when Macs became more popular.
Mine’s been trouble free for at least a decade, probably more – my Mac Mini is a 2010 model and I’ve had no problems since I’ve had it.