The price you see isn't the price you pay, as a Customer.!!!!

I bought clothing for my Grandson for over R1000 on Saturday 22 Feb 2020. There were about 15 pants that i wanted to pay for, for R20 each as per the price tag on ALL the pants, and I was told at the till that I cannot have the pants for R20 because it's marked R50 on the system and that Head Office doesn't work on Weekends and so there is NO ONE who can fix their problem. SO I asked the Sales Person AND the Manager to call me on MONDAY so I can arrange for someone to come and pay for and collect the pants I wanted to buy, and NO ONE has called.I dont think they will, because it shouldnt take so long, and WHAT HAPPENED to the Customer paying the price that the product is marked as.???????? I was still being understanding and patient by not making a noise about MY RIGHTS as a Customer...!!!!!! I would like to know what the delay is in calling me back AND why was I not allowed to buy the items for the price that they were marked as.????