Someone stole an offer from the market which was meant for another player.
Every item put on the market can be bought by anyone on the server. Adding a remark with a nickname doesn't mean you restrict buying it only to the respective player, anyone can buy it. Unfortunately, according to the game rules, this is not a breach of rules, and the Support Team cannot give back the items bought in this way by others on the market.
What we can advise is that next time make the exchange through the market if both of you are there.
Thank you for your understanding!