Buffalo Logistics ****ming Clients

I placed an order through Shein and got charged a Buffalo TAX payment of R500.00. I had paid the amount requested and then lodged a query with Buffalo logistics because my order had my sister's prom dress and i couldn't afford any delays. I called Buffalo logistics to process the refund on the excess amount charged. I was advised by an agent of there's named Desiree that customers get charged a service fee based on the area they live in. I then checked my proforma invoice and it has the incorrect address. I had explicitly told them that they have billed me incorrectly and they need to process the refund on the excess amount charged. They asked for a POP, i had advised them that this would not be possible as this was a 3rd party payment and not a payment through my app. So i had submitted a bank statement removing all the transactions irrelevant to them with the refund form and it is gone almost 2 months now and the refund hasn't been processed. I have over 30 emails in correspondence with the supervisor named Artie and the manager named Renette whom has not called me up until today to resolve the matter. When you call in at Buffalo logistics customer service and ask to speak to a manager, they are so rude to you and would never transfer you. By their behavior i can tell that they have been instructed to do as they are fully aware on the *******ion they have caused. I have lodged a complaint with Shein and still nothing has been resolved. I believe that i am owed about R300 from Buffalo logistics but this cannot even be confirmed as i am still awaiting a TAX invoice from with a detailed description of my purchase.