Incorrect order : missing food items

My family and I ordered 2 streetwise mix meals, 1 crunch burger meal 1 foldover and and extra box of chips. When we got home we found 2 streetwise meals with no mash, 3 boxes extra cold chips. When we got back to the shop we found that we were not the first to drive all the way from our home to complain about an incorrect order...... How hard can it be to get an order right, when everything you need to fill the order is right in front of you????