When I experienced strange difficulties in accessing my cyberbanking a couple of weeks ago, I went along to my branch to make further enquiries in person.
How was it, I asked, that the cyberbanking log-in page would not recognise my 'account number' as a means of accessing my account details? And moreover, how was it that the online customer help service had told me that my 'account number' "couldn't possibly be more than 16 digits", when it was in fact quite clearly 19 digits long?
Well, it turns out that the 'account number' for cyberbanking purposes is not the account number. Oh no. It's a secret number, for the use of bank staff only.
I could not extract an adequate explanation from them as to why the bank would need its own code number for referring to my account. Or why this number is ordinarily kept secret from customers. Or why they were now willing to share it with me. (Gosh, I can be a forceful fellow at times!) Or why the cyberbanking log-in page was prompting me for a number that I, as a customer, wasn't supposed to know, instead of the REAL account number which I did know.
Sometimes you just have to make do with what you can get, and treat it as a positive result. At least I was able to confirm that - for all regular intents and purposes (checking my balance, arranging inpayments from employers) - my 'account number' is the 19-digit one that appears on my bank card.
The status and purpose of the other 'account number' is likely to remain forever a mystery to me.