waited for more than 30minutes at drive thru

On Saturday the 6th of Feb 2016,I went to my favorite restaurant KFC in Silverton in church street around 10 oclock in the evening. I used the drive thru service hoping that I will get to enjoy my meal as soon as I get home cos it was raining and chilly outside. I couldn't believe it that I had to wait more than 30 minutes after I paid,and the lady who took my order didn't even bother herself to inform us that the chicken is still in the oven and will be ready after 30min ,worse part was when I requested to use their toilet they told me that I am not allowed to get inside the restaurant as they closed. Imagine 1 you are waiting for your order and when you want to use their bathroom they wouldn't allow me in? I had to look for a tree and pee under it,i ddnt have much of a choice. Ooooh my word when I got home,I found out that they gave me 2pieces instead of 3pieces. I didnt know that I have to check before I drove off,but now I have learnt a lesson.I would suggest that the cashier must tell the customer in advance if and when the meat is stil in the oven