Kfc wonderboom junction sucks

After going through the drive thru, i get told to wait in the parking lot for 15min, as everything on my order is going to take time. How is this even possible? I get overcharged on my slip, and have to stand and wait for a refund, as everyone just passes me. Not 15min, but infact 40mins later i only receive my order. Please tell me what is the point of having a drive thru option then, if you are going to wait that long?