I've just received a call from an unknown ID ("No Caller ID"). But no sound after answering the call and hang up after 5sec. I got missed call from No Caller ID before.
Seems fishy to me.
I heard there are cases where ppl phone bill/credit card get charged for expensive usage after answering the call. Is that real?

Not quite understand why amex wanted to hide its caller ID.. So that their customer cant call them back?

1. The guy from the Bank Negara, they called u or u called them?
2. If u called them, u called by the number that Ambank provided u or official Bank Negara number where u can found on its website?

I am sorry to hear that. Hope there is no lost in any form at ur side.
I'd got a similar call as well few years back.
A guy claiming from RHB called me, said that I have a credit card with RHB and owing them rm4k and ask for payment immediately. They came prepared with my IC No, my full name, my address, and so on. Of course I said I dont have any credit facilities with RHB. And they give me a Bank Negara number ask me to call to that number. Then, we hang up.
I end up didnt call that number but instead googled RHB call centre and called RHB to verify again. And, as expected I dont owe RHB anything and RHB confirmed that there were a scam going on using their name. And said that even if it is true that I owe RHB some payment, it is between me and the bank, NOTHING to do with Bank Negara. Banks will never ask u to get in touch with Bank Negara yourself.