McDonalds Rosebank-Worst service delivery

McDonalds Rosebank has the worst service ever! I am a frequent customer at McDonalds Rosebank and place large orders at a time (for delivery). I order from them every single week (I order between 10-20 meals, this may be tracked on the Mcdelivery site for proof) My orders are everlasting late. There are times I wait +- 4 hours for my food and the excuse is always "we only have 1 rider". My question is, if you know that this specific restaurant is always busy, why are you short staffed?! I place orders for many people and there are people who are diabetic and need to eat on time. I use the estimated delivery time as a guide, but as usual, no one sticks to this time and the food is delayed by hours.