I have already deposited 400 more dollars because they said that is how they verify the external wallet. yet i missed the 1% fee and need to deposit more funds in order to be verified. Is this a real thing that needs to be done in some cases or am I being scammed.
This sounds like scam to me.
Can I get my money back that I have deposited somehow?
If you deposited 400$ worth of Bitcoin, if the transaction is confirmed, there's nothing you can do. Bitcoin transactions are irreversible. It can be a case for the police, but they are not qualified for this and I don't think they'll bother.
If you deposited through bank, see at the bank if they can do anything about it.
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How on earth did you send money there without asking first? Why you don't just work with known and reputable exchanges?