FC mate have issue with Steam transation to SE

Well, today a fc mate talked about a strange issue. A month or 2 ago he purchased Sleipnir mount with steam credit. The $26 credit was taken from the account, however when steam try to connect to Mogstation to finalize the transaction, Mogstation is under maintenance so it didn't go through. However, steam took the money and now SE say it didn't receive it. Now steam refuse the refund since it claim money to SE but SE say they never got it.

All I can think of doing is put in a ticket with SE getting a form/email from them that says they never received the money and present that to Steam. Hope he gets his money back or item.