All casual does is unlocks your bootloader... it doesn't unlock your SIM or IMEI...
You will need to find a way to unlock the phone. Something you most likely can't do yourself, you'll either have to take it into Verizon and as long as it's out of contract and you don't owe them money they'll unlock it, otherwise find a third party service to unlock it.
If you go through third party services do your research before choosing one--be careful of possible scams....
Sent from my SCH-I535 using xda app-developers app
16GB Blue Samsung Galaxy S III (Verizon)... With a different ROM every couple days....
Custom Built PC- Running a tweaked, de-bloated Windows 8
Dell Studio Laptop- Running Ubuntu 13.04 (sold)