HOW TO GET 20% DATA BONUS FROM MTN
After that, you should receive a successful message from MTN (only if the IMEI hasn’t been used by another person) within some couple of minutes or instantly, saying;
Congratulations! Your smartphone has been activated to enjoy 20% bonus on any data you buy for the next 3months. DIAL *131*1# to buy your preferred data plan.
(If the IMEI has been used, you won’t get any response from MTN, all you have to do is to tweak again until you are successful).
Henceforth, anytime you subscribe for a data plan by dialing *131*1# you will get free 20% bonus for the next 3months. After these 3 months has elapsed, you have to tweak the imei again to be eligible for the next 3 months again. That’s how it goes.
For example: If you purchase 3.5GB for N2,000 monthly data from MTN, you will be given free 20% data bonus, which is 700MB. That’s how it works.
To check your data balance by dialing *559# or sms 2 to 131
Source: EntClass.Com