This trick works for all Airtel numbers and call can only
be made to airtel number only. Now dial these codes
accordingly
*337#
*700#
*700*1#
*700*2#
You will see something like this after dialing those
codes: Dear customer, you still have 100
free minutes.
HOW TO USE THE FREE CREDIT TO CALL?
Dial *337*2* airtel phone number# to use your free
minutes. Enjoy and don’t forget to share on your
timeline for others to get it.