We don't know the specifics of that issue. Some people are bound to experience issues, statistically. If you cannot verify your identity in another way there is always a risk in using 2FA. That's why I always keep Auth codes on file in case somehow someway it stops working. As for your specific case. It's most likely it has to to with the fact that you use a Chinese phone number. Makes sense as you experienced the issue on multiple platforms, keeping in mind the way Chinese networks and operators work. I know it sucks but if it was easy to lift 2FA there's no point in using it. Look, I'm not defending NB, just giving you info on what most probably is going on so you can take that up with them. They might be able to manually send that text.