Here is my advice...
Open a demo account on screen & Open a live account on screen at the same time.
Record the screen. It would be pretty easy to prove if it's a scam.
Run the accounts side by side on screen.
Demo on left, live on right.
Let it trade identical to each other.
If the live one is losing and the demo one is winning you would have pretty strong evidence that it's a fraud and they're just trying to rip people off I would say.