The missing advent calendar

I bought two advent calendars to send to my University student sons to help them through December exams and get them into the festive mood. Then I bought one for me, why should I miss out on a daily chocolate Christmas message?

No1 son says his arrived on Tuesday and he is enjoying his daily chocolate Christmas message. No 2 son is still waiting for his. Perhaps the wrapping was not secure enough and the postman is enjoying a daily chocolate?