You played for 20 minutes? That's 1,200 seconds. Three seconds each game [with all of the assumptions above] will bring us to 400 games at best.
Thought?
If that is 4700 bets, I would say it is impossible to place 4700 bets in 1200 seconds without using any kind of 3rd party help. But if it's 400 or even 800 bets, I would say it is pretty much possible. I have played Pragmatic Slots Dragon 888, and I am a master. When you enable turbo bet and disable animation from the settings, you can bet one bet each second. So, even if he played a thousand bets, I won't accuse him of using a 3rd party bot or software. But I am also surprised that the guy somehow wanted to blackmail the casino.