Where is my money?

I went to Pep store in Newcastle (Osizweni branch) on the 6th January 2022 to purchase the following items : Student Prints boys school shoes size 8 costing R129. 99, two girls long sleeves white shirts sizes 42 and 44 if I'm correct. Costing R95 each. Like any other shopper I swiped my bank card to pay as soon as I heard the message notification I was sure the transaction went through and I took my items and headed home. A month went by and as I was checking my monthly expenditures I noticed I was over charged during my purchase at Pep. Instead of R320 I payed R550 . I than went to the store to notify them of the error, I spent almost 2 hours in the store without them being able to trace my transaction inventory since I had no proof of purchase either than the EFT receipt because on the 7th of January 2022. My gran had went back to exchange one the school shirt and the shop assistant didn't capture the exchange in the system even though he was given the receipt of the initial purchase. He just took the wrong size shirt and gave the right size one and assumingly through away the previous receipt. He confessed when asked by his than acting/stand in manager. They told me to obtain a bank statement and return once the manager was back from her leave. So the sales assistants were unable to process my claim due to an untraceable sale transaction but could only find the trace of my bank card payment. They than told me that there was nothing they could do since the store manager was gone on leave and was due to come back after a month, and their access to retrieve previous transactions was limited. What puzzled me was when they told me it was impossible for the card machine to estimate a wrong amount since it was impossible to manually change amounts on the card machine or make two payment options in one sale eg pay by card and cash. That now for me raised suspision and the signature on the card receipt didn't look anything like mine. I don't even remember signing that receipt. I also had set backs, had to be out of town and couldn't go back on the day they had suggested I should come back since the manager was due to be back from leave. Went back again with my bank statement as they had requested, but again the manager was on her day off and I was due to travel again the following day. So I'm hoping through this platform I'll get help soon. My contact number is ***.