Extra charges for GPRS uses

Location/place: Bangalore

Name of company/service: Tata Docomo

Dear Sir I am Vijay kumar Tripathi using tata docomo post paid connection. My mobile no is 8050555510. I had used GPRS for very short time they charged bill nearly 1400 for 2 days uses(total approx 15 min). Let me know how can i complain about this Tata docomo customer care not accepting this as problem.

Let me know what action i can take againt them. I already paid extra bill for last month, this month i am not interested to pay.