Gtbank now offers an e-Top up service which enables her clients or customers to buy airtime credits right from their mobile phone without the need of downloading applications, entering your Atm card or credit card details or applying for a token. It is quick and simple to utilize, everything you need is your mobile phone containing the specific phone line that is connected to your Gtbank Account.
Code for Buying Airtime Credits from your Gtbank Account... Click here to see code: http://www.tolanisblog.com/2015/10/how-to-buy-airtime-from-your-gtbank.html

*737*amount# from the registered phone number.