iPhone 5 "Phone Number N/A" and device says Phone Number "Unknown"
So I just bought an iPhone 5 on Verizon off a guy on craigslist. Activated my phone,Clean ESN verfied by Verizon. I got home,put my Micro sim that I cut from my Android 4G phone,so it could fit. I can make calls and recieve texts, but I cannot send text messages through SMS. Only through iMessage. I turned my phone off and on but still nothing. The info on the phone Settings>Phone>My Number it says "Unknown". On iTunes, it shows "Phone Number N/A". Messages say "not delivered" Can anyone help??
iPhone 5, iOS 6