Shocking attitude of Manager and change of terms without informing patrons

I reserved a table at this restaurant in North cliff a week ago for 11 people for New Years eve. I was informed that there was no cover charge. I then increased the numbers to 16 two days ago. Once again I was informed that there was no cover charge. A friend tried to book today and was told that there was a cover charge of R450pp! I called in this evening and was told the same. There was no explanation as to when the cover charge was introduced. We knew this as a family restaurant where we could take our kids and relax on new years eve. The manager was not willing to explain anything and when I told her that we were cancelling the reservation for 16 people, she said it was perfect! Needless to say, that my family and I will never visit this restaurant again in the future as they are devious and do not inform patrons when they change the rules. And the management is also arrogant in not trying to find a solution to the problem that they created.