1. The first step is to Find the unknown number's Operator. For that you can take the help of Mobile number Tracing sites. Here are some usefull Links:
Indiatrace.com - Mobile Number Location Trace
BharatiyaMobile.com - Trace Indian Mobile Location & Operator
Go to any of the above links; Type the Unknown number and note down the Results. The result will be the "Operator Name" and "State".
Suppose your Unknown number is 9876547892 : After Tracing we Get the Result : "West bengal" & "Airtel".
2. Now starts the Trick: Search for the Ten Digit customer care Number of the Unknown number; Every state has a different customer care number; so be careful.
[NOTE: Search for 10 Digit customer care Number]
In my case I should search for West bengal - Airtel's 10 digit customer care number.
3. After you find the 10 digit customer care number - Call the customer care from a different Operator (Different from the Unknown Numbers Operator)
Suppose the Unknown Number uses Airtel; You should call from other Operators SIM like BSNL, Reliance, Docomo, Idea or Vodafone
4. When connected the customer care opt you for Languge selection.
5. After Language selection they will ask you: Are you a current User of xxxxx operator??
So Press "YES" or say "YES"
In my case they will ask me Are you a current User of Airtel?? So i will say "Yes"
6. Now they will ask you to enter the 10 digit Mobile Number (UNKNOWN NUMBER)
In my case I will enter 9876547892
7. Now they will ask you to enter a password. So enter:- 1234
[1234 is the default password of sim card; Most of us do not change SIM Password so there is 95% success rate of 1234]
8. After you successfully enter the Password - Now its your turn to seek Revenge.
* You can Know the Balance and Validity
* Activate Caller tune services
* Activate other Packs or subscribe V.A.S
* And many other things.
==CUSTOMER CARE NUMBERS==
Airtel – Kolkata 98310-12345
Airtel – Rest of Bengal 99330-12345
Aircel – Kolkata 98040-12345
Aircel – Rest of Bengal 98510-12345
BSNL – Kolkata 98830-98830
BSNL – Rest of Bengal 94000-24365
Reliance (GSM) – Kolkata
98830-98830
Reliance (GSM) – Rest of Bengal
98320-98320
Reliance 3033-3333
Tata Indicom – Kolkata
92310-08282
Tata Indicom – Rest of Bengal
92330-08282
Vodafone – Kolkata 98300-98300
Vodafone – Rest of Bengal
97320-97320
Tata Docomo- 90460-12345
( Kolkata 90380-12345 )
