Is it possible to score more than 400-430 in game of Brainium Freecell or how has someone got more 75 million points total?
You'll have to email the developers, because I didn't see any achievement or report regarding the Freecell game. If you see that 75 million points total, then it means the game has been hacked somehow. It's practically impossible to reach such score in a short time, even for leaderboards.
You can report this issue to the developers using the following page: http://www.brainiumstudios.com/site/index.html#contact