Waiter demanding TIP

On Sunday 15 November I took my daughter, a friend from Namibia and a guest from France to Cape Point. We booked at the Two Oceans restaurant and it was extremely busy, flooding with tourists. We were helped by a waiter named Gregory who helped us, but did nothing extra. We didn't have loads of cash in our kitty and after the bill of R687 arrived for very little food, we gave the waiter R700.00. He just PRESUMED that he got tipped R13,00and came back very adamant that we didn't give him 10% tip. (TIP by the way is an acronym for TO INSURE PROMPTNESS, which also wasn't the case here) I do know and acknowledge that a 10 % tip is custom for a table of 8 or more, but we were only 4 people and have the democratic right to decide whether we want to give a tip or not.. This was our French guest's first visit to South Africa and it had been very embarrassing, especially when the waiter told us they do not get paid, but live off TIP money. My friend remembered that she might have a spare R50 in her purse (kept for parking etc) and we gave this to him, totally flabbergasted. I (wild card member)have a sour taste in my mouth regarding this restaurant which up till now i loved to support