Extremely rude Manager

I Bought 10 pieces Family Treat with Twister Meals and 8 Zinger Wings. when I received the order I didn't check it immediately I went to the table, only when I got there I noticed that the sides and wings were not there. I went back and told them, They called a manager who literally told me that "I AM LYING" they always pack the sides. I then asked them to check on the bags as there were many bags packed there. The manager then left and one of the girls who works there keep coming to me to ask what the problem was and never come back. Eventually another girl came and I explained again. She then looked and found the bag. I then asked for that manager who said I'm "LYING" he didn't come and didn't even apologise after I wasted my time there. That was the worst experience of my life.