Terrible customer service at McDonald's Commercial Road

Every time we order through the drive through they forget to add something to our order even after repeating the order to us with the items included. Tonight they expected us to drive all the way around and stand at the back of a long queue to pay R12 because they forgot to add it... In a situation like this they could really just give us the sauce... It's not R100s or R1000s it's literally R12... Would you rather lose customers or sacrifice R12? The manager on duty was Sibukasi and was very rude even said it is not her problem yet they messed up the order.