how do i reset my data and voice usage? I have to always check on my usage as I'm subscribing to a limited data plan.

I assume you are trying to reset the usage in Options>Status 'BUYR'?
These cannot be reset as they are lifetime counters.

Try this free app, BlackBerry App World - DAVID

OR

A better featured, paid version. https://appworld.blackberry.com/webstore/content/14626