Hl7802 gsm

Hi,
Nice to meet you
I have bought few HL7802 module sample and trying to connect with GSM mode in India. Since it supports 2G fallback.
We have requested module name , it giving as HL7802.
When we requested to see available RAT AT+KSRAT=? , it gives us +KSRAT: (0-1)
But HL7802 should allow to change to RAT mode 2 (GSM mode), since "AT+KSRAT=? " not showing GSM mode I can’t use AT+KSRAT=2, it gives ERROR.

Could you please help me to enable GSM mode, what i am missing here ?
How to enable the GSM mode in HL7802, Do i have send any other commands to enable GSM?