I would fire this manager

Some friends and I had a meeting regarding helping to uplift our community. We didn't have much money as we use our extra to feed the poor so we ordered 3 plates of chips. When I asked the waitress how much it is she said R18 which seemed fair then we got the bill and it suddenly changed to R36 per plate which is ridiculous!! We were tolld by the very pompous manager that it's R18 for a side order of chips and that we had had double portions! He took 2 half portions off but had such an attitude! If he worked for me he would have been showed the door