I think a basic principle with limited plans that offer the ability to buy extra data is "You should be able to actually load the account platform at the 2G hobbled speeds in order to pay". The heavyweight website/app for the mobile network, combined with the use of a phone number-tied Android login as primary login credential rather than a user account, it meant that the only way to actually get 4G back online was to have access to wifi on the phone in the place & time you needed to re-up; If I did have that access at work, I wouldn't need the data.

Despite years of being too lazy/anxious to figure out phone number portability, I ultimately ended up switching carriers from Simple to Mint because it was just too annoying.