Cannot change plan

Hi,

My plan rate increased to a point where I would like to select a slower, cheaper plan. I have tried to do this through the app and through the website but neither has worked, when I click the "Change Plan" button the app or website would get stuck in a loop and sometimes would stop the loop saying "Please try again". I have tried multiple devices, different browsers, and even different days/times but nothing works. This is very frustrating as I do not want to have to go to the physical store every time I want to make a minor change to my plan.