Refusal to release goods ontime

I am not going to name the shop I had an issue with but as a paying client I think I have right to choose what time / date I can collect an order of baked goods. I had an incident with a local business that told me what time they can have my baked goods ready (ordered a month in advance) instead of the time I required it to be ready. As I work in the service industry the last I checked the client is always right even if they aren't with in reason.