I ordered from shein ,my order was R 2800 and I paid customs for R 670

I ordered from shein ,my order was R 2800 and I paid customs for R 670 .I later received email saying that my items is lost in transit ..And they are willing to pay for the package only not for the money I spend in customs ,how is that ,I am have to loss money ,if they are refunding me they should refund me also the money spend overall