Shocking behaviour from rude owner when i called h...

Shocking behaviour from rude owner when i called her out on over charging me!
I attended this cafe today as it looked pleasant enough from the outside. I ordered my breakfast, paid and i found the waitress delightful.
I went back up afterwards to place another order as i was still hungry, this time an older lady was at the desk. I noticed after the payment had gone through that she had over-charged me. I pointed this out to her in order to be sure it was her mistaken and perhaps not mine.
She abruptly answered that surcharges were their policy. I informed her that she hadn't notified me of this prior to charging me, and its not the amount that matters but the fact it was a hidden payment.
She replied that "all their customers are aware of the policy", to which i replied i was new this is area and it was my first visit to this cafe, and as nothing was advertised or informed, i was totally unaware and had not consented.
She rudely responded, "well i don't care if you don't come back!"
This shocking, rude, unprofessional response all because i was asking her about my rights !
Its a shame that if one has a voice and wishes to question any hidden payments, they get treated so appalling at this place.