I had an experience recently where I told a person behind a counter to please give me two dimes and a nickel. She had no clue -- she did not understand U.S. currency or coins.
I told the manager of the place that I just could not understand why she would put someone at the counter who did not understand U.S. coinage. All I got in return was a sullen sneer.
I would imagine it is easier to skim the till and blame the innumerate for the 'shorts'.
You were addressing the manager is English?
There's the problem, she didn't understand your complaint.