Pick n Pay paying R2500 for nothing

On 13 November 2017 i bought groceries for R3000 odd I paid with the cash on me and swiped R2500 seperately. After swiping the cashier told me unfortunately the transaction did not go through and she can unfortunately not give me the groceries. I went on to my bank website on my phone and confirmed that the transaction did go through. I also went to the atm outside the store to print a receipt. The cashier told me that she cannot give the groceries as it says unsuccessfull transaction on her side. A manager was called and confirmed this. She was heavily pregnant at the time. After a week and no transaction being reversed i went back to the store. The manager was on maternity leave and someone else assisted me. He said i needed to come back when the accounts or admin staff were on duty which i did. Again when i went back he said i needed to bring bank statements, why couldnt he have told me this in the first place. I was very buzy at work and some time passed. Eventually i printed my bank statements and went back. This time they told me i needed statements printed at the bank with a stamp. I couldnt understand why they couldnt just check on their system surely there must be some way to also confirm this from their side. I even went onto the banking app on my phone and showed the manager but he wanted stamped bank statements. I had death in the family in December and was away and very buzy at work. Today took time off, got stamed statements and went back to the store. It took me forever to explain to the manager. He kept misunderstanding me thinking that i got the groceries and the transaction was done twice. He took every effort explaining to me that there is only one transaction.....uhm i know that. But i did NOT get my groceries for that ONE transaction. He then called another lady and i had to explain AGAIN. He then asked for my number saying they will phone me. Someone just phoned me now asking why is the amount R2500 exact did i try to draw money from the cashier. I explained AGAIN.

It seems that ive been ****** and nobody helps me I dont want the cash back i just want to buy groceries for that amount is that so hard to understand!???