This piece of information will guide you on how to secure your bank account and update your personal information, it doesn't matter if you have Gtbank account or not because the same thing goes when you don't update any old phone number linking to your Bank account. How is that possible? Nice question, Gtbank also explains how your old number can be acquired by another person, maybe you just lost your SIM card or just decided to change your line for some personal reasons. Well, the bottom line is that when you lost your Sim or don't use it for years then network operators have the right to re-sale your old line to another person since you are no longer interested to use the phone number again. Don't feel surprised when you call your old phone number and hear it ringing and picked by another person because it's possible, though that's not the main issue here. What if the same line being used by another person was the phone number you used to open your account and forgot to change it. The Implication of another person using your old phone number linking to your account is that the person can be receiving alerts which might as well contain your balance and other personal information that shouldn't be seen by someone else. The good news is that Gtbank made it easier to change your old phone number and other personal details without calling customer care support or visiting the banking hall, I equally have the video from Gtbank that will guide you on how to change any of your data through their internet banking platform. Before watching the video, let see how you can avoid your phone number being used by another person. How to retain your phone number
If you still need your old phone number then always keep it active, at least now that most smartphones allows you to use more than one SIM card. When you lost your SIM, simply do welcome back to retain the same phone number. However, you might deliberately decide to let your phone number go by dumping it, you even have the right to cut it into pieces but make sure the number is not linking to your account. How to change your old Phone number linking to your GTbank account

account To change your phone number simply watch this video and follow the step by step guide but remember you can as well update other personal details and not just phone numbers. In case you are unable to watch the video especially those using the Operamini browser, you can follow these steps.
Step: 1
Visit: www.gtbank.com and login with your User ID or any email address linked to your account.
Step: 2
Navigate down to the left-hand side and click Self-services menu and then to Cusomer information update, this will take you to another page. On the page, you will see New Request button, click on it and choose what information you wish to update.
Step: 3 Once you are on the New Request page you will be able to change the following details

Your Name

Phone number

You address

Date of Birth

Now select any of the above and input the right name, phone number, and your residential address. If there was any mistake on your date of birth then you can as well update it. Hope this helps.