Charged R34 for tap water, when caught just told sorry

We asked for tap water along with some other items and were charged R34 for the cup the water came in without it being made clear we are being charged for the cup. I querried the total amount as it seemed a lot. The manager came and messed around on the computer after the initial server "lost" my slip with the info of what I was charged for.

After 10 mins they said oh yeah we charged for the cup... "sorry" and reversed the amount for the cup. 10 mins of wasting our time making us late for the movie and frustrated. I asked them if they were going to do anything else apart from just saying "sorry" and reversing the amount for the cup? They said no- I responded that they must not have had much customer training to not offer some kind of compensation after causing us to waste 10 mins and get frustrated after catching their "mistake" (it was never identified whether it was intentional, have caught Ster Kinekor service staff "accidentally" charging for large smarties when small of are ordered etc...)

They didn't offer any kind of recompense for the time wastage and frustration...