Hi Insula,
I am also from the Netherlands.
Don't be happy they allowed you to deposit your funds. You can deposit your funds to anyone you walk into on the streets. For instance Nigerian scammers, they also allow you to deposit your funds to their account.
Be happy when you are allowed to withdraw your funds when you need or want to.
I used to be able to withdraw funds, but some time ago Bittrex changed their policy without any notice upfront.
Check my thread https://bitcointalk.org/index.php?topic=2627675.0
Been waiting over 50 days now to withdraw funds worth some thousands of dollars.