Customs amount just a thumbsuck?

I purchased a helmet from a company in the UK which I paid R2k in customs / duties to Fedex to clear and receive it. The value of the helmet and goodies inside was +- $620.

The helmet was the wrong size, I had to return it to the UK, the company made me pay a shipping label for DHL to send it back which I did.

They exchanged the helmet for the correct size and sent it to me through Fedex again.

Before they even shipped the helmet, I reached out to the agent that handled my import, and asked what I needed in order to not have to pay customs again as I had already paid for this item. They advised that I needed the export clearance docs and if I could provide proof that it was returned and a new one would come to replace it, I wouldnt have to pay it again.

I was able to get the docs from DHL, and provided them with the original payment information (invoice and POP) as well as the info for the new shipment from the company for the helmet - INCLUDING a statement from DHL declaring the shipment and manifest the helmet was on for the return.

Not only did Fedex not communicate ANYTHING with me through the process, I was forced to pay an additional R4200 to clear JUST the helmet through customs this time - where the value of just the helmet (excluding the other gadgets it came with the first time round, with a value of only $475).

Now how can the helmet by itself which costs less than the original import cost double in customs clearance for LESS ITEMS??? (the extras were a bluetooth headset for the helmet, additional visor / anti-fog pin-locks that I kept and didnt have to send back, I only sent the helmet back to be replaced)

I emailed Charlene Fester on 17 October 2022, I got a response saying "they will look into it" on October 24, I have since sent follow up mails asking for an update but have received absolutely no feedback at all from them.

What's taking so long?