Don't Lose My Number lyrics

As far as I can tell the song is about a young man who is falsely accused of a crime and only Collins believes in his innocence. This meaning seems very apparent throughout the song to me, and if we go through the lyrics they maybe become clear to you too.

First verse:
The police come looking for the young man in the night asking about his whereabouts (obviously those that they question are scared either for or OF Billy, and Billy himself is scared of being found). No evidence against Billy was found nor any trace of him. Billy swears never to return to town (he will not turn himself in because he is innocent) Collins believes in his innocence (and that he will never return). The last lines suggest that maybe he did something that looks like a crime but it either wasn't him or it was for a justified reason. (some kind of accident. Maybe killed someone in self defense by accident or something like that.)

Chorus:
Basically just telling Billy that he believes in his innocence and that even though no one else believes him he should know that he can contact Collins when he needs to but that the responsibility is his since even Collins has no idea where he is hiding from the Police.

Verse 2:
Still looking for Billy. They don't know Billy like Collins does; as someone who would not commit a violent crime. They never took the time to ask for Billy's side they simply assumed guilt. The latter portion of the verse is Phil Collins recalling the incident that got Billy into trouble. people hearing Billy yell "get out of my way" and then shooting someone (the blinding light) and then he obviously took off down the street running past Collins.

Chorus again.

Bridge:
So all the "don't give up" stuff is pretty self explanatory at this point. Continue to run and hide if you know you're innocent and that Phil believe he is innocent. The Run for your life part makes me think maybe death sentence? So again adding to the whole, shot and killed someone idea.

And so on.