So here is the image showing my recent deposit being taken out which was not me. But they only took the deposited amount and didn't take the rest . I deposited a small amount to see if it would help me find a way to sign a message for verification. But idk if the one I did is correct and don't want to post something that could cause insecure info to breach the account

This is very common with custodial services like casinos and exchanges. When you make a deposit, they will sweep the funds into either cold storage or a hot wallet. Freebitco.in had a certain threshold where if a deposit was too small it would not get swept until much later, which is why the $15 deposit was untouched for a while. As long as your balance is credited with the amount you deposited, you have not been scammed. If you have the private key to the specific address where any of these deposits originated from then you should be able to sign a message.