Just like the Glo welcome back bonus, 9mobile welcome back offer and the Airtel 20% welcome back bonus, MTN also introduced its own welcome back bonus for it's returning customers.
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With the MTN welcome back bonus, you will get 2000% bonus for calls & SMS to all network and pay-as-you-go browsing. This offer is available to all MTN customers who haven't used their MTN sim for 45 days or more. The MTN welcome back promo is valid for 3 months.

If you have not used your MTN sim to make/receive call, send text message, recharge or browse in the last 45 days or more then you are automatically qualified for the welcome back offer. All you need to do is to insert your MTN sim into your phone and recharge with at least N100 airtime.

If you recharge with N100 airtime, then you will be rewarded with 2000% the value which is N2,000 for calls, SMS and pay as you go browsing.

Below is the full list of bonuses you stand to enjoy depending on the amount you recharge
Recharge of N100 gives N2,000
Recharge of N200 gives N4,000
Recharge of N400 gives N6,000
Recharge of N500 gives N10,000
Recharge of N1,000 gives N20,000

500% of the bonus will be for calls and SMS while the remaining 1500% bonus will be for pay-as-you-go browsing. Your main airtime and data balance won't be deducted until you exhaust your bonus.
For the bonus airtime, you will be you will be charged at 80kb/sec (N48/min) while SMS at the default rate is N4/SMS capped at 75 SMS weekly and data at the default rate is N5/MB.

How to Check your Balance
To check your balance, just dial *559*65#.

Note: You can't use the bonus airtime to subscribe for any Value Added Service or data plan.