Glad that you opened a thread about Jetwin here, the telegram could be a trap, if you decide to talk via telegram be sure you will not give in if they want you to deposit again, scammers are heartless they will try to scam you many times until you figure out hat they are indeed scammers, if you cannot get your money out it's the end of their business anyway, the money is quite big to be ignored.
Everything is correct. Conduct correspondence only where you can really be sure that you are conducting it with Jetwin's representatives.
If they decide not to pay you money, their reputation will be tarnished. In this case, it will be important that as many people as possible find out about this, I am sure they realize this and will not do stupid things.