you are not the primary account holder, the person who is disable it via tmobile.com.
or the website just went on strike.
to fix it have the primary account holder call customer care, and have them fix it... this may include the deletion of mytmoibile account and recreation.
Hey there! Just checking in here to see how things are going. Are you trying to log in to my.t-mobile.com using the primary account holders phone number or email address? Are you the primary account holder? What specific error are you getting?