Wal Mart cakes. I'm done with them!

I went to a wedding reception on Saturday, and they had cakes, like all receptions. I was talking with one of the two brides when I chuckled and said, "You both got white cakes huh." She half smiled and said, "Well, I ordered a chocolate cake, but they (Wal Mart), called two days ago and said that they could not make the chocolate wedding cake. She did not go into details and I did not push for an answer as I could see that it bothered her. What the heck is up with that? There can be no reason or excuse as to why they should not have been able to make that cake. Why didn't they say something at the time of the order? It makes no sense! I have been becoming more and more displeased with them for their cakes anyway, but this takes the cake, so to speak. I will NEVER order another cake from Wal Mart.