Many players trusts a bit too easily promises made by other players to exchange their house lot for credits or even ask your account info (email & password) to participate in a contest. Some players may even offer you to buy gold for your account if you send them lots of credits.
BE EXTRA CAREFUL!
The only safe exchange in the game is buying items from someone else. If you do trust another player and get hacked or lose credits, it will be YOUR responsibility.
Sorry for the direct words, but I get emails almost weekly of players that got scammed and needs me to do something about it. Your account is your responsibility and you will have to live with your choices.