Can I unlock a Galaxy S4 SCH-R970C?

[JonNewType]

I recently got a Galaxy S4 SCH-R970C from my mother because she upgraded her phone. Her network was Cricket but I live in Jamaica
so for me to use I need to unlock it, but from what I'm reading on the internet I am wondering if it is even possible.

Is it ? and if it is how do I go about doing so?

Your responses are greatly appreciated!

 

[Rukbat]

She can contact Cricket and ask for the unlock code, but since it's no longer on her account they may not give it to her. (If it's on the account and paid for, and there's no outstanding balance except the current month, they have to by law.) If they won't, look on eBay for unlock codes, It'll cost you about $25.

How? When you put in the SIM card, it'll ask for the unlock code. Put it in (carefully - you only get a few tries) and the phone's unlocked.

 

[JonNewType]

She called them and they said they don't have the code for that phone. What should I do now?