I'm sorry this happened to you but you're not going to receive the sympathy here that you are looking for. Your son didn't qualify for the contest (is he even old enough?? you described him as a child).
Your description of the situation (Heartbreaking, Outraged, Really affected my family so deeply, We were all sitting there heartbroken, One of the most miserable experiences we have had on a cruise to date affected our Christmas so negatively, a family sitting there after being treated like an afterthought, A mother crying, father angry and son heart broken) seems far beyond an appropriate reaction to something like this.
Again I'm genuinely sorry that this happened to you.