It was a crash, server restarted since we use auto-restart. The server have not saved the transaction yet before the crash, so it's like you've never purchased the skin since the server did not take the money and you didnt get the skin.
Notice for all players:
I've seen server crash multiple times for the last few days/weeks but i still cant find the cause of the crash to solve it. If you know or think any command, event or anything that might have caused the crash then let me know. If you use any command or did something before the server crash, then try to repeat it after restart to confirm it. If server crash again after repeating it, please report it in forum.