No details on what the refund was for. Double billing? Incorrect billing - as in never made the purchase ?
Refund requests by players from their respective Apple/Google stores are a no-go in this game.
SGG processes refunds, any refund, by deducting gems from player’s gem bank balance in his account, based on their prescribed gem-equivalent value.
Say your mate bought 4800 gems.
Used 4800 gems.
Asked for refund.
SGG docks your mate’s account by 4800 gems.
Net result = negative 4800 gems.
Your mate has to make good the gem deficit to continue playing this game. Within the proscribed time. Otherwise his account will be banned once grace time expires.
The only reason your alliance colleague is showing a negative balance of gems is - if he purchased them, used them up and after using them requested a refund of the payment.
If his money was refunded then it’s right that SG then deducts the gems used which will put the account into a negative gems balance.
If everything has been actioned correctly and there is no mistake (technical error) on either side, I am sorry but there is no work around.