Bad service

I went to McDonald's Hamilton today 9 January 2020 around 16:00, by the drive through. I ordered a Mango Frappe, waited for 30 minutes for my order when they brought my order it was wrong. They brought me a strawberry Frappe, I told the lady that brought it that I didn't order that. I asked for the Mango Frappe, she then tells me that they don't have the Mango they only have the strawberry. I don't understand why I was not told when I was ordering and only being told after waiting for 30 minutes. Today they gave me the worst service ever.