The MAS & app issue has been resolved , as I deleted the app from the finder Applications folder because from the launchpad the particular app didn't have the x sign for deletion , the opened the App Store & installed it again from the Purchased Apps list . Now it is shown as installed in the app review page .
Couldn't resolve yet the second issue that regards the iTunes , but I am starting to believe that it has to do with the Cloud Beta .
Anyways , we shall see .
I am pretty sure that there's two answers for you.
Find the app that u think that u didn't buy....in spotlight or finder..
Then delete it by app delete,clean my mac,trash can or any delete app..
Make sure that there's no app in ur Mac..
Then Go to App store again then go to the app ...which u deleted
It show money in purchased item....then presss option key for 10 s then click that purchsed item again..
For me,That is worked !