I had a T-Mobile prepaid plan on a drugstore Android phone from 2010-2012. The data usage app they preloaded on it was almost a day or two behind, so if it showed that you were close to hitting your cap, chances are you probably already hit it if you had been using your phone a lot in the past 24-48 hours. I caught on when the app told me that I had almost two gigabytes left (back when you could stretch a gig out quite a bit if you stayed away from video apps or downloading big files), then I got a text from them an hour later saying that I hit my cap.

Granted I was on a plan that had "unlimited" data that throttled my phone to like 128 kilobits per second when I hit the cap, but it was still deceitful as fuck for people who were on plans that charged extra if they went past their cap.

It's crazy that phone companies are still pulling this shit.