I have a prepaid plan. I could not ADD FUNDS to my account. With the help of someone high in T-Mobile he got me to try changing my browser. I have Windows 10 in my laptop. I used Microsoft Edge. I have full access to the site. On a computer and another laptop (both have Windows 7) I have access to the site. That suggestion worked! I removed the T-Mobile app, because it did not work at all!