I think the problem is when cross border fraud happens, the complexity and cost for detective work is higher than domestic fraud. Also in case of regular refund

I think the problem is when cross border fraud happens, the complexity and cost for detective work is higher than domestic fraud. Also in case of regular refund for customers, it is much easier for Market institution to deduct fund from domestic sellers' accounts. While cross border market has to deal with tax, exchange rate and different countries law regarding for refund.