Driver is running late aka no stock!?

My delivery was scheduled for yesterday before 5pm. 16:45 I received an email that said that the driver is running late, please be advised that your order is with the delivery partner. Today 15:37, I contacted the call centre. They saic that they didn't deliver, because they don't have stock. Why do they allow me to order and pay if they don't have stock? Now I have to make another plan because I planned to bake it for my guests tonight. Totally unacceptable of WW to email me that my order is with the driver if they don't even have stock.