The Nigerian communication commission have merge all Network code to be same
So from today if you have MTN, Airtel, Glo and 9mobile
Use the following code…
Eg *556# to check balance is not working again
New code is *310# to check balance in all network.
All previous codes like *556# for account balance in MTN and codes like *131# for data in MTN and all other network codes will no longer be valid from today.
The newly posted codes will serve for all networks, starting today.