Secure Virtual Currency System

I am creating an app in which I need a very secure point system (virtual currency system). I can make it all on code and save them with playerprefs, but that can be hacked very easily and manipulated by the users. I need a point system in which everything happens server side. So I looked into Parse Cloud and also Kii, but there documentation and support, feels highly weak for us Unity users. I have been stuck on this for quite a while now. Do any of you have any advice for me?

try Tapjoy, they can get the job done for ya probably.