In message , at 00:58:36 on
Sun, 17 Jun 2018, matthew3774
remarked:

Hi guys I had £2.87 in my Natwest business account. This account has no
overdraft so typically doesn't let me spend if the transaction would
take me below £0.

Anyway yesterday I made a journey from Victoria to Highgate, from
Highgate to Victoria, Victoria to Westminster and Charing Cross to
Highgate. I was able to touch my contactless card to open the barriers
for all these journeys.

Today I was unable to use the card when getting on at Highgate to start
my first journey of the day.

That suggests Natwest refused the full charge for the previous day.

Is there a chance that Natwest will heavily charge me for using
contactless when there was only £2.87 available? Or is it possible that
all the trips only cost £2.87?

Since coming home I have topped up the account for when the money is
taken out by TFL so it shouldn't go overdrawn

I don't know if TfL will periodically "retry" the charge, or what
happens next, and what timescale the card's blacklisting by TfL will
wear off.
--
Roland Perry