The used of USSD is trending especially from GTBank they keep on performing wonder check out how to lock your bank account in GTbank using 737
This is a new feature to all GTBank holders
in case of any unforeseen emergencies
where you’ll need to lock your gtbank account instantly.
lock your account if you are caught in the web,
you can simply dial *737*51*74# using any mobile number in Nigeria free of charge.
You’ll be required to provide the phone number registered
to your account and your 737 pins.
To unlock your account, call GTConnect or visit any GTBank.
This will at least prevent scammers from hijacking your account.
Source – Yomiprof