Call blocker App - Windows Phone 8

WIndows Phone 8 currently lack any apps that enable users to block unwanted calls or text messages. I need someone to develop an app similar to multiple iphone or android call blocking apps available. It should be simple, user friendly, and its primary function is to block calls and texts from certain numbers, with the option of removing that number of the block list or adding multiple numbers. Refer to: [login to view URL] The above website reports a similar type of Android app that has the relevant functions I'm looking for for Windows Mobile. It should be called: "Call Blocker" for Windows Mobile. The key is simplicity, with large user-friendly icons. It should also record history of how many calls and texts it has blocked and from which numbers allowing the user to document history.