MTNOnDemand is not yet available to all Nigerian banks, For now, if you are a customer to any of the below banks, you are eligible to use this new MTN services;
The service is easy to use, all you have to do is just to dial *904*amount# to top up your phone from your bank account. Meanwhile, there is still another fast method to recharge any network in Nigeria either with internet access or without. Also with your mobile banking app, you can top up your phone by using the Airtime option there, it's very easy the fast.
You can also recharge your MTN line by dialing *131# then follow the on screen guide that will be given to you by MTN system.
These methods are very simple, time-saving, cheap and more convenient than going to get it from vendors.