Did you fail to log out off imessage on your old phone?
Find someone with an iphone put your sim in and then log off imessage.
I did turn it off on my old phone and iphones won't take thr new sim card that verizon gave me I tried that.
Go to: https://supportprofile.apple.com/MySupportProfile.do
Log in if not already logged in.
Click on "Edit Products"
Click on the "X" to the right of the product.
Turn your iPhone on airplane mode.
Retrieving data ...