No customer orientation

At around 10pm on Monday the 30th of November, I ordered a small McFeast Deluxe meal with a Fanta through the Drive Through. I was told that I couldn't get a small meal and when I enquired why, I was told that the system only started with Medium meals. I alerted them that I bought a small meal at another branch not so long ago and requested that they check with the manager on duty why I couldn't get my small order. Instead of getting the manager to attend to my query, the entire staff came to see who wanted a small meal. No manager came to address me which left a bitter taste in my mouth. The branch might be new, but if they are not ready to serve people, they should spend the extra time training their staff. I'm seriously disappointed. Had I not had a long day at work, I would have thrown my toys around professionally.