How can my Bird S199 mobile set be unlocked?

I purchased a bird s199 moble in March 2006. The moble dealer told me that I had to use only Airtel sim card that attached with that moble set for 12 months. After one year I could use any sim card. As it has completed the time period of one year I tried to put a Hutch sim card into it . The mobile asked an eight digits pword I dialled zero - zero eight times and my mobile locked permanently