McDonald's Verulam

McDonald's verulam gave us 2 items short on our order. This order was placed online. When I went to collect, they said they were having technical issues with their screen and could not see the contents of the order. I then showed them exactly what was ordered. After 45 minutes I received the order and queried the 2 burgers that were not given, I was told that it was part of the meals. I left and later found out that it wasn't actually part of the meal. I laid a complaint on their website and received a call from who I believe to be the manager a few days later. I was told that the footage would be looked at and they will get back to me. A week later and nothing has been heard from them