Stolen chocolate

Hello again, I have just discovered that a box of chocolates that were given to me from a work client which my children asked to eat but I said I was going to think about if I was going to let everyone in the family have or if I was going to use them as a gift to someone else to save us some money. My husband store them in our cupboard and every time I was asked about them I maintained that I was thinking about it still. I certainly was feeling the pressure to let them have the chocolate but I was not convinced that I should give in to the pressure and especially as the younger child was so impatient about it which she usually always is. She never likes to wait on things, she ate all her advent calendar chocolate in one day too. They were only very small but still they are not allowed sweet treats from Monday to Thursday but only weekends. I need to still find out if the 14 year old child has been helping the younger child with taking the chocolates, even though she has never even mentioned the chocolates at all. However, she can be very deceitful and I am pretty sure she is in it too. I have just found the box less than half empty. What do you recommend I do? And is there something I should have done differently so they didn't feel tempted? I don't like to hide things from them but we usually have to. I have at the same time found that they have also taken another bag of chocolates that I was going to give to some of my students. I had bought two bags one for our girls and one for my students but I have just found that they have also stolen these too even thought I gave them their bag. I feel so disappointed and angry that I want to ban chocolate for the rest of the Christmas season.