*****ulently transferring airtime via My MTN App

I have been ****med by a person stating he worked for MTN ***** division which obviously was a false declaration i realized later on. Pls be aware your one time pin issued by MTN on the My MTN App is valid for 24 hrs and not valid per transaction. So if a *****ster got hold of your OTP they can transfer your airtime, data, minutes etc to anyone they feel like - you will get a sms notification "you have logged into your MTN account" which is actually someone else, they call you and request that OTP nr. and are so convincing, professional, soft spoken, respectful etc stating they are calling from MTN and in such a manner (stupid of me) obtain your OTP. Pls be aware of this **** going around, do not trust anyone and DO NOT GIVE ANYONE YOUR OTP, NEVER. I was caught this time but never again.