3g working 2g not working not registered on network

I just got a note 3 SM-N9005 as a gift from my relative in uk. Unlocked in india Problem is gsm only mode never worked, if I changed it to gsm only it just shows emergency call only. WCDMA and LTE works just fine, just gsm only not registered.

As I traveled a lot to an area with poor connection or with just 2g only available, the phone try to change to gsm mode but it never get registered, just showing emergency call only. factory reset it numerous times, but the problem still not fix.

Anyone can help me, please...