Order outstanding for more than a month

I have a app**** for credit to buy a XBOX for my child for Xmas. On 13 November it was approved. Today is a month and a week later and still I haven't received delivery and every time I phone I get told it will go out for shipping. I can understand if companies have stock issues, but why are they still advertising something they don't have stock off and why can't anybody just give you an accurate answer on when expected date will be? Why lie? VOX came highly recommended to me, but I'm really not happy now. What will I tell my child on Xmas day?