I don't see the issue.
> You went gambling
> You won twice
> You left the table
> You returned asking about the 4 times in a row winning
> He told you if you bet 25k and win 2 more times, you'll get the 70k winnings.
Not a scam as you left the table, you should be happy he offered you to continue playing for the winners, but you'd have to play 25k games.