whats wrong with my samsung d500?

if had it for about 6 months and it was working fine at first untill my camara stoped workin every time i went on it it would go back to the main screen and when i went onto my video camara it would show a exclamation mark in the bottem right hand corner, after the my phone became more slower and begain to freeze more,then about 3 weeks ago it freezed and the screeen went white and has not been workin sience could any one help me or have experiance the same probolems? xXx