Woolworths 3 for 2 special is a ****

So on Tuesday I find out that Woolworths has an online 3 for 2 special on baby clothes. Placed my order and paid according. Today I received an email telling me that the third item I ordered was out out stock without any mention of any compensation or replacement item. I am very convinced that the 3 for 2 was a ****. I mean why was I able to add an item that is out of stock to my cart and be able to check out. Woolworths better replace my third item or take the whole order back and refund my money because I will not be cheated with a non existent 3 for 2 special where I only end up with two items.