McDonalds Wrong Order and Cold Food

My friends and I went to Mcdonalds to get some food from the drive through and we placed some specific orders. Then after arriving home we saw that the staff only gave us half of the order. We then had to get in the car and drive all the way back. We then queried the McDonalds staff, and they were totally clueless about what happened. We supplied them with the receipt, and only then did they find the rest of our order. By that time the food were already cold, and we also realized that they did not remove the onions from 2 of the meals as we asked for. This was not the standard we are accustomed to from Mcdonalds.