I have seen many situation as you before OP and those experiences were from known exchanges a few years ago. Lucky those people that have been helped by the team to receive the wrongly sent bitcoins to omni layer/protocol.
But this time, it's hard to reach and make the exchange do the favor to you and might just say that it's your fault.
Hi, thank you for your reply. May I ask you why you think that exchange now may say me it's my foult ?. May you explain this a little bit? Is it about of Poloniex company or about of me ? Thanks..
Every exchanges clearly mentioned about this in their terms, crypto assets sent to the wrong address maybe lost permanently so make sure you are sending to the right address in direct or indirect way so the fault is clearly on your side.
However the exchanges can refund the funds to the user in matter of minutes because they received the funds but since the terms favouring them then they choose which way to go on case to case or by time to time.