Airtel — airtel postpaid number activation charges

Address:

Thane, Maharashtra, 400604

I was using airtel postpaid connection, as i shifted to another country for 6 months.
Number was not in use and become inactive.
I am ready to pay 3 months rental which is 299 as not informing airtel, post which services are discontinued. Airtel asks me to pay 1571 as number activation charges for 6 months. As per plan i should get rollover unused data and free minutes. As i have not used single call or used even 1 kb of data. Airtel denies to do same.
I am long time airtel user. They dont agree to make it prepaid also, as number is not valid.
So only to activate number i will be paying 1571 which seems unfair on my part.
I just want to utilize my old number.
I except fair amount to be charged and fair services to be given.
Regards
Sampada