Airtel — postpaid bill adjustment

Hi,
* i was shifted to pune in aug where airtel network was zero.
* i wrote so many mails regarding this to airtel but no one helped.
* atlast i had to swithoff my number when they said this problem cant be resolve now it will take time.
*now i shifted to vadodara and i want to resume my services, for that i asked airtel to clear my bill for the duration when i was not able to use airtel because of there nwk problem, now they are denying.
* as per them they are asking to pay the bill, why should i pay the bill when i have not used airtel.