Can I use old company Blackberry as a personal device?

My company stopped using Blackberrys a couple years ago. I still have my old one, I have the same carrier can I use it on my personal account?

Reason I ask is I have a blackberry (that works) and when I put my sim into the old work one I can't make calls and the data doesn't work.

I thought it would be simple enough just to put my sim into the old phone, but I guess not. What do I need to do to get it to work?

You may need to get ahold of the carrier. It would also be really helpful if you would post information like the carrier and bb phone model.