Disappointed with order cancellation

I have recently ordered on more than one occasion from Macdonalds Pavillion Durban via Uber Eats and every time the order was cancelled by the store. What annoys me the most is that the store would be busy with the order and after about an hour to an hour and a half they would cancel. My family and I would be anxiously waiting our order only to find it cancelled after almost 2 hours and so we have to reorder from another restaurant as Macdonalds is unable to service their customers. I have proof that this has happened to me 5 times in the last 2 weeks. What kind of service does macdonalds offers. This is totally unacceptable to have your order placed and paid for only to be cancelled a few minutes before expected time of delivery.