blackberry 8520 warranty question

[lala1493]

I upgraded my old blackberry to a curve 8520 sometime last year; and then in december i was surprised with an iphone. Unfortunately, recently my iphone has been having a lot of issues and could not receive phone calls; so I contacted at&t to reactivate my curve 8520. I've been using it for about a week, and i will admit there is a little wear and tear on it but nothing serious; the phone is having some major software issues though too; always freezing, lagging, always having to pull the battery; and all i really do on the phone is text, call, and occasionally use facebook. I do have insurance, but I wanted to know if it was possible instead of paying the premium if i could contact the at&t warranty department; and if it would be possible to swap out my 8520 for a newer curve model like the 9360? My friend went from their iphone and downgraded to that phone, and they say it's an awesome blackberry and they never have any issues with it. 

I will admit now that im back to my blackberry, I do miss it. I still have my instagram and everything on my itouch, so I feel as if i have no use for an iphone or to go through all of the hassle of the iphone insurance when i have a blackberry still; but i wanted to know if the warranty department could accomadate to swap out for a newer model even if it's refurbished considering I only used the phone for a few months; and it has software bugs and issues despite me upgrading the software on it, etc. thank you very much =)