charging exhotbident charges for using data card 3G

I have used datacard (AIRTEL) HARDLY 4 DAYS (DURATION 1 HOUR/2 HOURS) FOR WHICH THEY HAVE SENT THE BILL FOR RS.4825/-DURING JULY AND FOR THE     MONTH OF AUGUST FOR RS.1818/-WITHOUT USING  DATACARD  IN SINGLE MINUTE.   RS.58/- FOR THE MONTH OF SEPTEMBER.I HAVE ALREADY SPENT RS.2000/-FOR PURCHASING DATACARD.(WASTEFUL EXPENDITURE).I DONT WANT TO CONTINUE OF YOUR SERVICE. I WANT TO SURRENDER MY DATA CARD.  P.NAGARAJAN. AIRTEL NO.8754436788. RELATIONSHIP NO. 1024408203