bad attitude from cashier(without a name tag) in Jubilee mall

Went to McDonald Jubilee mall to buy Oreo MC Flurry and i actually felt sorry for the cashier who assisted us and the rest of the team working on that schedule,because they condoned the bad behavior i received from the cashier. She said they were out of Oreo for my order so they cannot assist me,she then went on to the advertising menu board to point out on the Oreo picture and the MC Flurry, two three times saying "we are out of this(oreos),so we cannot make this Mc flurry)- i asked if that was necessary as i got confused,She said that is what they told them to do because not everyone understands the language and it's easier to point out,she assumed i did not understand and this was funny in a sense.I walked out as i felt i could not take the stupidity anymore,she then went on to make some remark as i walked out and they all laughed.

I demand a formal apology,