Service Delivery

I am a regular customer at Pizza perfect for the simple fact that they make great food. The quality have the food has never been question no matter what the day it is always fantastic, my problem lies with the quality of service. Every single time i have gone to the place i wait more than 30 min for food, when i get my food they always forget something from my order which i then have to wait again for. Or they are out of stock which i only get told about after i have paid for it. They don't smile at you when you come in and when you question them they just respond with \I don't know". Look I'm not saying i will never go there again i just feel maybe customer service can be improved on. """