Just change your imei with samsung galaxy tab and open your browser and open https://airtellive/offers.com and confirm your mobile number and get 4gb 3 g data for 2 monthes.
for change your imei you can use engineering mood,
go to mtk -cds information- radio information-
in imei box type imei for change your imei
if you cant access engineering mood then root your phone with king root or for samsung phone use kingo root.