Ozbargain's favourite travel debit card can be a real pain in the ass sometimes. After having used the card to withdraw cash from ATMs many times in many different countries, my card suddenly failed. 'Authorization denied' the ATM told me. I called Citibank's shitty automated system, and finally got through to the Phillippines call centre (but only after calling their Citi Prestige Service Centre and asking to be transferred). Their solution was to go back to the ATM (half an hour walk) and try again. It didn't work. Solution - try again in half an hour, we can't see anything wrong on our end. Cool, thanks guys.
Did a bit of Googling and found that the fix was to make a transaction in a shop to 'reset' the card. I was able to withdraw cash again straight away.
My experience with their app has also been painful. I registered for mobile app one time pin (which is required each time you make a transaction) prior to my departure. Every time I have changed sim cards, the app deregisters me from mobile OTP, which requires another long and arduous call to their call centre.
I love the card, but don't love Citibank.
Hmm I've never needed the OTP for ATM withdrawals, only for online transactions, which I never needed to do since the card is only for withdrawing cash.