Airtel — Network Issue in Qatar

I have got the Airtel Prepaid SIM card from India 2 months back.
A yearly recharge has been done in this SIM.
For the first 2 months the SIM was working well.
Suddenly one day the network went off.
All types of trouble shooting done.
But nothing happened.
So I left it like this.
After 2 full days the network came back again on it's own.
Now after working for 15 days again since today morning the network has gone off.
Please advise me what is this issue all about and how could it be resolved completely.
I have not made any complaints to airtel yet because I am sure there is no response from them as per the comments posted in this forum.
Thank you