Bad service Mc Donalds Southgate

I placed an order on the self service device which was quick, i checked my order against the the monitor and it was not there, I patiently waited for 10 minutes and it did not appear, I asked the lady at the do if the monitor is working and she said no, i was so irritated because when I went there to pick up my food it was cold. I asked the lady who was handing over the food to me to switch of the monitor as it is confusing us, our numbers are not showing in the monitor, she said, it doesn't matter whether the monitor is on or off. That was the attitude she gave me. Bad service I receive and it is not the Mc Donalds standards I'm used to