When you dial *131# on your mtn line, you are given a list of options or menu of what you can do on mtn to make communication very easy for you. But it's amazing to note that most of these telecom operators are taking Nigerians for a ride without giving quality service in return. They milk a lot of money from Nigerians without reciprocating it with efficient service delivery.
It's highly disappointing that the NCC that is saddled with the responsibility of carrying out oversight functions in the communication industry is doing little or nothing to protect our people right to access to quality and affordable Internet service and the likes.
Below are the codes for registration for mtn data share but you will be surprised at the response after going through a lot of stress to register.



How To Share Data On MTN Network

To share data on MTN network, take the following steps
Dial *131*2*1# or text REG to 131; to register for MTN Data Share, you will receive a unique security PIN
You are required to change the system generated PIN to a new PIN they can easily remember by dialling*131*2*5# or by texting Change OLD_PIN NEW_PIN NEW_PIN to 131. E.g Change 0000 1234 1234 to 131. Where 0000 is old PIN and 1234 is your new PIN.
After changing the PIN, you are required to add beneficiaries to your MTN shared Data Bundle account via USSD menu *131*2*2# or by texting Add <MSISDN> <PIN> to 131. You can add up to 5 beneficiaries.
Once you have added beneficiaries, you (the sponsor) will be able to share your available data bundle among the added beneficiaries by sending the keyword Share <PIN> to 131 or simply dial USSD code *131*2*3#.

Good luck!!

Have experienced the same, I even thought I missed a process and eventually got tired of trying.