You could post something like this:
I placed an online order during my lunch break and arrived to pick it up at the scheduled time (2:05 PM). The store had already been notified of my order, but when I got there, my sandwich still wasn’t ready. There were two employees working, and although one was busy with other customers, several walk-in customers who arrived after me were served before my order was completed.
I ordered ahead specifically to save time because I had to return to work. If online orders aren’t prepared on time, it defeats the purpose of ordering ahead. I ended up having to leave without getting my food because my lunch break was over. Very disappointing experience, especially since this was my first time ordering from this location. Unfortunately, I won’t be ordering from here again.