contract killer 2 has locked up on level 20 chapter 8

I have been playing contract killer 2 and am now on level 20 chapter 8 the game wont let me open contracts or challenges but the only thing it will let me do is spend more money on up grading weapons etc. I would like your assistance in the matter or if it cant be fixed i am either looking for a full refund or set me up with a similar game with credit .