Disappointing customer service. Case advisor can't even be bothered to update me on progress of my missing payment that is the fault of the bank.

Last week I ordered groceries for R904. Not all the items were delivered so another amount was deducted for R761.47 for only what was given to me. The first amount was never refunded so I called the store and asked for help. They said the bank needs to reverse the pending transaction. The money is gone from my account and my statement reflects that. I asked FNB to please sort it out and they told me its a missing payment, gave me a case number and told me it will take 21 days to sort out. Does FNB think I have 21 days to wait for almost a R1000?? This is unacceptable, a client's missing money should be sorted out with top priority. It's like FNB does not care whether people need their money or not and how we will survive for the month so long as the bank is making money. My case advisor has not even bothered to give me a update yet on what they have done. This should not take longer than 5 days to sort out. Deeply disappointed with this bank and I swapped to it because I heard FNB was amazing. Clearly that's not true.