Rustenburg disgusting service

We got 2 large chocolate milkshakes at Mc Donald's in Rustenburg today, drove all the way home only to find they were sour, tried calling the phone number in the slip it just go's through to fax line, drive 7kms in after school traffic back to the shop spoke to a lady the customer experience manager she went and got the shift manager Vumeka.... Oh wow so rude, while I was trying to talk to her she just walked away from me so I followed her to the till, I tried to talk to her again she walks away and goes into the back she came back and I raised my voice and said can you please just listen to me I am trying to talk to you... She looked at me like I'm stupid clicked her tounge sighed and said yes... I told her first off I'm not happy as our order in the drive thru was wrong and as I'm in pain after having my shoulder rebuilt a week ago I was not in the mood to go in store to get it changed like the cashier told us we have to do... I just wanted to get home... So we get home and as I am a huge fan of the choc milkshakes from McDonald's took a nice big sip only to projectile vomit as the milkshake was sour. The shift manager clicks her tounge and says it can't be sour but she will give me my money back for the milkshake. I said to her is this how you apologize to customers that have been inconvenienced? Again clicking of the tounge... I asked her for head office number or email address so I can lodge a complaint but she said there is no number or email she said I must go on the website printed at the bottom of the till slip when I told her there is no "contact us" option on the website she just shrugged her shoulders, she refunded me the money for the milkshakes and that was it no I'm sorry for the inconvenience or anything. Please can someone get back to me regarding this as I am far from impressed. I am a restaurant manager myself and I know if I treated my customers this way my boss would fire me on the spot. Not only was the milkshake disgusting but the service from Vumeka was aswell.