Never heard of an exchange asking for a refundable security deposit in coin listing but if that's a big exchange like you mentioned, I don't see any problem with that as no way they will put their name on becoming sh*t as it will ruin their reputation.
But anyways, can you disclose in public the name of the exchange? We can get a better response from the community if the name of the exchange will be mentioned. And are you sure you are dealing with their legit representative?
I have actually dumped the people I was talking too, because of suspicion of scam. The exchange was Bithumb.
I also doubt that big exchanges would charge a security deposit of 4 BTC (lot of money) and refund it later. I guess that once you have sent the 4 BTC, you will never heard about these people.
I do not have 4 BTC anyway, so the discussion was over. But I am still doubtful, I haven't seen articles or reports about these kind of practices, so if it is a sophisticated scam, it is good to report it here and let people know, to avoid some people losing all to these scammers.
You're right for stopping that discussion. If not, then you will lose your money.
To confirm that they are an official team, usually through the contact support on the site and through the Exchange's official telegram group.
To list tokens on the Exchange does require a fee and the fee is non-refundable. Usually they offer several options such as multiple trading pairs and marketing bids. They generally have a proposal to offer.
