Right or Wrong?

On last saturday night, I brought my sons to go to convenience store (7-eleven near my home) to buy soft drink. They were very thirsty after we came back from my mother's home after dinner. This is our habit between me and my sons. During the shoping at that night, that was interesting a story there.

It was a bustup between the counterjumper and customer! For a soft drink worth HK$5.0!

The story was that, as we know, there is a soft drink machine for the customer to fill the drink by themselves. After they paid in the counter, customer got a empty paper/plastic cup and they went to the machine to fill which they wanted. There was a customer there told the counterjumper she gave her a wrong paper cup (for softdrink A). She wanted a soft drink was using the plastic cup (for softdrink B). But the counterjumper mentioned that the customer called for soft drink A but the customer clearly mentioned again she wanted a soft drink B. The customer told the counterjumper may be she heard the calling wrongly. And then the counterjumper change a plastic cup to her but during the exchange of cup, the counterjumper made emphasis the customer was ordering softdrink A repeatly. I believed that the counerjumper talked to customer at least five times for this. And then the bustup was started, and they shouted loudly and there were at least five people stood in front of the door to watch what happened inside. At the same time, I got my paper cup and filled the softdrink with my sons, and left the scene! When my family was leaving there, the bustup was not stop yet, and the customer was calling to the shop owner for complain...

I felt it was very funny! HK$5 almost made the ladies to fight there.

I have some questions to myself,

No matter the customer made mistake for calling or not, she should respect the customer. Just exchange the cup for customer and said, "that's fine, I will change it for you!". Nothing will happen and the customer will satisfy the service perfectly, actually, the shop has no any lost for the incident. Why she repectly emphasis the customer made the mistake?

For the incident, although the handling way of the counterjumper was not good enough, but is that really need to complain to the owner of the shop? May be the counterjumper would lose her job for a cup of soft drink. Can she explain to the counterjumper the she has wrong way to handle the issue? What is the right way to service the customer?

Actually, what is the right way to face a mistake we made? I don't know, but if we think we never made any mistake, it was absolutly wrong. Sometimes, the absolutly correct is incorrect , do the right thing, not do the thing right!