I got a transfer ban

Two days ago I received a transfer ban, even though I didn't do anything against the rules, and I can't understand why. Please lift it. I'm someone who constantly invests money in the game; you can check my history. Before the transfer ban, I put a card up for sale with 300,000 coins. After the ban, neither the card nor the coins were returned to my account. I'm quite distressed right now.