Got my Pre Plus a few days ago.
Is there an app that shows how much data you have used?
you might try this homebrew solution out
you'll need preware to get it, http://www.preware.org/#/index/
Sprint Pre- Meta-Doctor 2.1.0 w/Flash
Everything is Amazing & Nobody is Happy, "People with their mobile phones, "uh... oh... it won't..."... GIVE IT A SECOND... IT'S GOING TO SPACE!" Louis C.K.
Thanks, Will check it out.
Preware was the 1st thing I installed when I got it.
Edit: Just downloaded it. Exactly what I needed.
Glad I could help!