If I can withdraw my btc from bittrex in the future,I never use again this exchange

Don't act like Bittrex did you any harm -- they just follow the rules that fit within the long list of regulations exchanges have to deal with. If you will be able to withdraw your funds, it means that you have verified your account, and from there you can continue using Bittrex -- verification is a one time occurrence. Man up and handle it accordingly, because the longer you're not doing anything, the longer you can't get your funds back, it's that simple.