You're put on the trading greylist when you've bought something from the store for USD normally, it might also do this when you get unbanned, not sure about that tho.
Normally you're removed from the list in 24h hours.
Didn't hampa tell you on #toribash that it happened because you were spamming the chat and the game AI added you to the list? Stop doing it once you get removed and you won't need to make threads like this