Terrible treatment by staff

On Saturday morning in Killarney Jhb, I purchased 2 items totalling about R 285. The sale went through on my phone and banking app, but never showed on the shops system. I showed all 3 ladies working there the email confirming the sale, as well as the FNB app message. They insisted it never went through, told me I needed to leave my card number, which I refused. They then told me I needed to pay again, which I refused and showed them once again the email and FNB message. I told them I had already paid and was leafing with my goods, the lady who I believe was the manageress, physically blocked my exit and tried to grab the bag out my hand. She then took the bag with my paid for items and walked to the office at the back and shut the door in my face. Outside the store 3 centre security guards were waiting, while explaining my position she walked out and handed me my bag. Appallingly handled by the staff, I will try very hard to never shop at any Mr Price again