Disappointed by McDonald's

My family and I went to get a sharebox from McDonald's which costs R192.00 which is not a problem. On the menu it states R2 for every sugar drink thereafter which would total to R200... But when it came time to pay they charged me R2.50 for every sugar drink. When I had asked why the extra charge they couldn't explain. When I had brought up the charge that is stated on the menu they said that there was nothing they could do about it. When we got home the big Mac was dry and hardly had any sauce on it and the Cajun burgers cheese and tomato was basically on the side... What a disappointment from McDonald's and the sad part is that it's not the first time that this happened. The only reason why I go back is because my son loves McDonald's but if it was up to me... I wouldn't go back.