How to deal with a shady exchange? I'm new here and the reason is that I believe I became a victim of a 
scam. And hopefully, you may guide me to get out of this shitty situation or at least help me expose the scammers.

I've been stupid and got into contact with a guy called Glen Morley through telegram who supposedly has a very high accuracy signal rate on bitcoin trading, which he did actually, assuming that the exchange had genuine charts. We made a deal to split the profit 80/20. He didn't ask for any private info or whatsoever. He directed me to open up an account on bitfami.com 

After the first day, I was almost sure that it was a scam. When I tried to withdraw the next day, the exchange told me that I'm not allowed to withdraw because my account was new and I have to wait for 4 business days to do so. It appeared during that conversation that they are also charging a 15% tax if your profit exceeds 20k USD. I've been also encouraged to continue trading in the meantime and they couldn't give a reasonable explanation of why to do so. When I asked why they have such rules nowhere to be found on their site, they became mute.

As I wasn't allowed to withdraw, I decided to go on to see the outcome of this story assuming that I've most probably lost my initial investment. Glen sent me signals to trade and I ended up with 5,9 btc from 0,25 btc in a week, just by 5 trades a day. In the meantime, I kept on thinking about possible scenarios but couldn't make much sense of the situation.

After a week, today, I made my last trade today to figure out the whole setup. It appeared that the 15% tax of the total profit made that they were mentioning was supposed to be deposited in order to withdraw which is something they don't mention. It's not even written anywhere on their site. In my case, it's around 6,400$. I don't have that money. Even if I had there's no way I'll deposit again to a shady exchange that comes up with last-minute surprises. When I told Glen about this, he encouraged me to pay it by getting a loan! I believe that the guy so-called Glen and this exchange are operating together. At first to convince people to deposit, then to make them believe they're making fast profits and at the end to make them deposit ridiculous amounts to withdraw which would probably never happen. 

Sorry for taking your time with this but I feel like it is my duty to spread the news and ask for guidance if possible.

I have screenshots of every conversation I had with the exchange support and with Glen in case it would help.

Any help is appreciated, thanks in advance.
This is either a scam or it's not. It's very easy to tell which:

Case 1: There are no actual signals that make a profit. In this case, it's a scam. Case closed.

Case 2: There are actual signals that make a profit. In this case, who cares whether it's a shady exchange or not? You have the signals -- trade larger amounts on a legitimate exchange, never try to withdraw from the shady exchange, and outsmart the scammers. You still make money.

But I'll bet dollars to donuts it's case 1. That means there are no signals that makes a profit. That means there is no profit. That means there's nothing to withdraw. The means you're wasting your time trying to withdraw funds that don't exist.

It's your exchange account, right? That means you can see what trades it's making. You can check on other charts whether those trades will or won't make a profit. Either you have profitable signals or you don't. In the former case, you're going to make money. In the latter, you can't possibly make money. You have everything you need to tell with.

But we all know which one it is. The signals don't exist.