Good App but i had a problem

Its a good app but i had a problem, i bought the Full Upgrade($2.99) while using this lite version and then i configured the login/password but decided to change it for another. After using for a while, i closed it and reopened to test the login/password. However the app showed a messenger saying that id have to reinstall the app to configure the login/password again and when i unnistaled it an reinstalled i notticed that i had lost the Full Upgrade($2.99) ! How i can contact the producersor the apple store?? Becareful another buyers...

PauloGustav0 about Sex Positions, v5.0.2