Well that is no good at all! Is the line that you are trying to manage a hotspot device or a tablet of some sort? If so, are you attempting to log into the my.t-mobile.com account using the number that is set as the primary account holder?
Hey syrus_truesd! I just wanted to check in and see if you'd made any progress with this! If you're still having trouble, do you mind letting us know what type of device you're using on this line?