just you have to send One SMS for that.

* First You have to deactive all mobile office services from your mobile number. How ? Ask Cotomer care to do so.
* After that Send “MY DATA” to 543210

I got this news from One of my closest friend Jigar, By his opinion , Now a days All his Airtel Cards are renewed with 100 MB Usage.

those users who got renewed 100 MB usage , comments below so, other users can have better idea for using Trick.