I used to work in telco (in another country) and it's a difficult line to tread. 95% of customers have no idea what their 4 digit PIN was so you have to identi

I used to work in telco (in another country) and it's a difficult line to tread. 95% of customers have no idea what their 4 digit PIN was so you have to identify them other ways, and not being able to access their account is the kind of thing that pisses even legitimate customers off (which is why it's so easy to take advantage of). Our company's policy was "if they don't know the PIN you have to connect them to the call centre and have them verify for you" but customers are rarely impressed to be handed a phone to the overseas call centre. I know I got it wrong at least once.