For this trick you need to have a lifetime airtel sim. If you have a 999 lifetime sim it is best. Just keep your balance between 15 to 20 then activate mo after 2.30 pm. It will get activated in 4 hrs. After activating just reduce your balance between 12 to 14 by making calls and just remove your sim from phone and don't use it for 3 to 4 days. After 4 days you will see that your balance will not be deducted and your mo is also activate. It works 100%. Follow each step strictly.