I am using a prepaid SIM with my blackberry. First, BB messenger is not working and I can't figure out why. Also, my aunt gave me the phone and it still shows her number and her email addresses. The phone won't let me change. I have already registered my personal ones on the TIM blackberry website.

You need a BB data plan for any RIM based services such as BBM and email. For her email to stop, she needs to call the carrier she used and cancel her BIS account.