System down and all of a sudden prices change

On the 28th of July I was at tembisa macdonalds... we got there and they told us their system is down okay that's fine we understood and waited like 10 minutes. After waiting we try order the specials on the app then they told us its not working. I than ordered a normal macdonalds meal of which showed me that it was 47,90 on the screen and also on the adverti*****t screen, when the guy gave me my change it was R3 short then I asked him why and he said the probably changed prices that's why the system was down. I DO NOT UNDERSTAND HOW ANY OF THAT IS ANY OF MY BUSINESS BECAUSE THEY DID NOT CHANGE PRICES ON THEIR SCREENS THEN THEY TELL ME PRICES HAVE CHANGED . While waiting for my order one of the employees try to buy food via the app and then ALL OF A SUDDEN THEIR MACHINE WORKS ! AFTER WE ORDERED SOMETHING WE DIDNT WANT ! And the main reason why we went there was to get app specials... we ended up spending more than expected AND WE STILL DIDNT GET OUR CHANGE ... Please get back to me as soon as possible .