Missing / Out of stock items

We placed an order using the sixty 60 app. I selected my alternative items and my account was debited with R433-81. When my order was delivered I found missing items so we called for assistance and were told the missing items are out of stock and were advised to go to Checkers Valley Hyper for a refund. When we arrived there we found that they did intact have plenty stock of the items we requested. On asking can we please just get the items we were turned away as head office could not give them authority to do so. So we had to go in store and purchase the items that were not delivered and now have to wait to be refunded.