Sim card locked, unable to turn off option for Sim...

I accidently locked my SIM card. I was able to follow the instructions to get the PUK code to unlock my phone, but every time I reboot my phone, it is asking for the PUK code again. I went into the settings to turn off the SIM card lock, but when I tried, it did not allow me to turn it off, gave error "Pin turn off not supported".

How can I turn off the SIM card lock feature?

Thanks for your help!