Connection barred and Fake Charges

Location/place: Mohali

Name of company/service: TATA Indicom/Mobile bill

Dear Sir,
On 24th August I switched over to Tata Docomo from Vodafone(7508000193). I took a plan of 899 rs per month against the unlimited out going ( local, landline and std). Which means I have to pay only 899 Rs plus taxes for month and I can use unlimited phone calls. Yesterday I got a lot of messages from Docomo that I have crossed the limit which is 6000 and I should pay at least 6000 rs for continuing my services, and after that last night they barred my services. When I called at customer care they said we can’t tell you anything because your bill has not raised yet and they will be able to inform me after 72 hours. Till the time I have to wait. Sir, how can I survive without phone for 72 hours as I am working in a professional company where I have to report to my bosses thrice a day on phone and to deal with customers and distribution channels on phone during closing of month. This statement was given by Mr Rohit Yadav singh at customer care at 9:43 AM in today morning, ie 27 Sept. more over he was unable to solve my problem rather he was trying to convince me to wait for 72 hours and to make a payment of 6000 Rs. After that I visited Docomo store, see rector 37C, Chandigarh, where Mr Anuj confirmed me my outstanding of 8932 Rs which is ever highest usage of phone in my 10 years of experience. Again Mr Anuj was unable to inform me why such a high bill is generated and he himself admitted that this is just a harassment by company.
I spoke to Mr Sushil Kumar at customer care at 11:55AM, And I asked him the procedure of disconnect my phone number but he also said the same thing to deposit the payment of 8932 Rs then they will disconnect my number and I will get my security after three month by cheque which is 850 Rs.