No refund for double payment

I ordered an item as a birthday gift for my wife on 09.06.2021 (order number: ***6) and initially wanted to pay cash on delivery but the system wouldn't allow the transaction to pull through on that so I made an immediate Payfast payment (for which I received e-mail notification 09.06.2021 14h31)

When the courier came to delivery my parcel on 11.06.2021 he insisted I pay cash on delivery as this is the instruction he received - no matter how much I tried to proof to him that payment was completed on this order he insisted I sort it out with Takealot self...

So I had no choice but to pay cash as well as I really needed this birthday gift for my wife the following day...

I've send numerous e-mails trying to get a refund on the double payment I made but after 4 different people responded to my request and each promising to relay the information to the relevant department it's been 2 weeks and nothing has happened yet!!!

So they are more than happy to receive payment immediately but seems if the error on their side is made the is absolutely no regard to trying to get it sorted