Holiday in jeopardy because of your incompetence

On the 2nd Dec, I made a booking for my family in St Francis Bay from 18 Dec to 25 Dec (a family of 4). Based on this booking, I booked my other travel arrangements all the way to Durban thereafter. I just received a call from the resort to ask me the ages of my children which is 16 & 13 and they said that the until will not be suitable for us. Please note that nowhere in the booking from RCI did it ask for the ages of my kids and now this is my problem. In all my previous booking at Dhikolo or Mount Amanzi, I book a 4 sleeper and have no issues. Now, your agents tells me that I was supposed to phone the resort and find out if the 2 kids are allowed. What is the point of booking online, a 4 sleeper and not being able to sleep 4. I have read the terms and conditions before paying and it clearly states that sleeper couches are for kids under 12 and I understand that. However, when making the booking it does not say that 2 will sleep private and the other 2 on a sleeper couch. I am not an idiot to book a unit that we will not be able to use. I want this resolved TODAY