KFC keep on taking items away from my order

I just had it with KFC Glen Marais. Almost everytime I order food there, whether it's the drive thru or inside, they always leave out some items. I made a point of checking my order before I leave. Today I ordered through the drive thru but couldn't check my order as it was a large order and they were extremely busy. When I got home, some items in my order was missing. Tried to call them but the number is engaged. Absolute pathetic service.