Yes, we know about Bitmart exchange, because they have a BTT account here: @BitMartExchange, they have indeed eaten victims/thefts etc., maybe you are the umpteenth victim of the Bitmart exchange.

Like this person is also a victim of the Bitmart site.
Topic: Bitmart SCAM!!!

My advice to you in the future, if you are already familiar with the Bitcointalk forum and want to do crypto trading, try here first to get information about the exchange, at least, members here are detected all over the world, so you are a bit spared from scam exchange sites, with the information from the community here.