Refund is in Xsolla balance which is unavailable to me and what can I do?

Recently I have a refund from marketplace and it is put into Xsolla balance. Xsolla had been the payment processor till November 30th when I found out it isn’t any longer. This change was quietly made by Epic which seems like such a coincidence afterwards. My refund is put into Xsolla balance by them and Xsolla is suddently unavailable to me. Techinically I have lost my money due to these two operations combined. I have sent 2 emails to marketplace support and got 0 reply. What a terrible experience.

In any case, whatever happend between Epic and Xsolla is not my business. Any change by Epic should not cost me money and Epic should take all responsibilities of the transactions in Marketplace.
What else can I do to catch their attention and get my money back?
I seldom do international transactions but this is a lesson learned from Epic: look out your wallet as they can steal from you.

Finally the refund is put to epic wallet.Epic wallet has a problem though: it doesn’t support partial payment, for example $100 balance and $120 order, then it won’t work. You can only pay order less than $100, like $80. Then you have $20 left in balance and so on. Eventually you will have some money that can’t be used. Hope they can support partial payment in the future.