By his name i can easily figure it out that he is an indian(i am also an indian)
Moreover you can easily see on a loading screen the "made by 7thReactor" message, and the app version etc.
I didn't got the message:-"made by 7thReactor" is your logo ???
If yes then i think that apple will surely take the decision to ban him.He will lose a $100 account
Actually one should never sell the source code until and unless the process is very clean.Also,if the game stolen "is just similar" to your game then sorry,no action will be taken because history says itself(every game is a derivation from another game !!!)
Or prepare an email asking apple to ask the developer for the source code(tell them that you have the source code).If the developer is not able to prove that the game was ever made by him then even his future in app store will be banned
but if he just took ideas from your game and then himself made the game then sorry !!!(remember mark zuckerberg)