Nokia5130

Hello, i need to format my nokia 5130 Xpress Music. When i select option to restore all factory settings it does not accept the code 12345, 0000, 1234, 123456. I never changed my code. If done mistakenly, how to restore original security code? My phone memory is getting low although no content in it except for system files and application. When anything deleted, the total phone memory decreases instead of free memory. Plz help. BuG