In the mean time you can tweak this Airtel IMEI and get 500MB, 2GB, 4GB depending in the sim.
I did it on 2 Sims the first got 500mb while the second got 2gb.
To get the Gigs Tweak this imei below
Send keyword Join to 141
This are the new imei for those who are having difficulties :
Huawei B683 Airtel 4gb
Imei : 356346041089563
3g to 141
NOTE : IT ENTAILS PATIENCE AND ENDURANCE, A LOT OF NIGERIANS ARE TWEAKING AS YOU ARE ABOUT TO STATE YOURS, SO TWEAK TWEAK UNTIL YOU GET GB… BEST OF LUCK.