WHY must I pay for Mcdonalds negligence !!!

On Saturday (21st November 2017) my girlfriend and I decided to get some McDonald’s after a movie. In the drive through we placed our order, 1 Med Cajun Meal, 2 Cheese Burgers and a Jalapeno sauce. The lady then informed us that they have run out of all drinks and only orange juice and powerade was available. We took the orange juice, for the medium meal. To my amazement they charged us for the juice as extra, when I queried this with the pay counter they said they can’t do anything about it because it’s the way the till is set up – REALLY!!! In today’s time that should not be happening, you can override or something? This is totally ridiculous that I must pay extra because McDonald’s are unable to keep a tab on their stock levels and order when needed. If you guys had the stock I would not have to pay that extra money. The money was only R5.50 but the principle behind this matter, is that you ran out of stock for something that I wanted and now I must pay for something extra! (Interesting thought: The drive through was full, now every single car in that que had to pay R5 / R10 extra depending how drinks they took, this would have boosted you takings for the day making business look good, when the reality is that the customer was boosting your profits because of someone not managing stock correctly - My company builds software> I feel I should offer you a solution, once a low limit is reached the system automatically reorders for you) Going forward I am not sure if I can support you again, I was really under the impression that you looked after your customers. But from this incident it’s very clear that your priorities is somewhere else!!! Because of that I am forced to take my business elsewhere, plus inform the people in my circle of how *********** McDonald’s really is and their negligence is at our expense! Farewell McDonald’s !!! R5.50 cost you much more !!!!