Loyal but disappointed

I went to the steers on Thursday 26/11/2015 at around 14:00 for lunch. I ordered a combo deal which consists of a burger a regular chips and a 330 can. I was then asked if i wanted to upsize to a medium chips. I agreed upon this as an upsize means you pay a bit more and still recieve what you pay for. The advert with an upsize meal stated that i will then recieve a 500ml buddy coke. As i recieved my order i checked it back at the office and then discovered that i got a small chips and a normal get real burger with no coke in the packet whatsoever. I then went back and the packer said i must bring back the chips. I did and then she gave me a different package with the same amount of chips ( a small ) and also enquired about the coke leaving out that i recieved a normal R10 burger. She then rep**** its because i upsized. I then said i upsized because of a medium chips and a 500ml coke. They refused to correct the order and I paid almost R50 just for a normal burger and small chips. I would have rather then taken 2 seperate burgers and a coke and chips which would have been cheaper and still get value for money. I am highly disappointed by this as Steers is always my first option.