Don't use Discovery Card for international transactions!

I have a Discovery Credit Card. On 9 November 2018, 8700 Dirham went off my account to pay for a hotel. On the same day the transaction was reversed - again for 8700 Dirham, The rand amount that went off my account was R35 217.47 but the refund amount was only R32 038.26, even though there was no change in the Rand / Dirham exchange rate. I have struggled since 6 January to get this resolved - the only feedback I have received was confirming that the exchange rate did not change. However, they are now blaming it on Visa fees. My understanding is that Visa fees are between the merchant, Visa and the bank - nothing to do with the customer. I have asked them 2 weeks ago to provide me with more detailed feedback regarding the visa fees, but I have not received any feedback of any kind. It has now been 7 weeks, NUMEROUS calls, promises of feedback but nothing...