I all - I have a BB Key1 and cannot change the ringtone - The file appears empty.

I have to say after a few years with it I am reasonably happy.
Had to repair the screen that fell out one day and have the whole brain re-formatted but its still working well.
Cannot play the ringtone in settings - it asks me which prog. to use and suggests AUDIO, but the file is empty.
Have I accidentally deleted it? It's the same for notifications - the file is empty.
How do I reload the audio files for ringtones and notifications?