did Robert sing the song stolen?

Is "stolen" the name of the song? Because if it's its name, then no, he didn't sing it (at least not in Twilight).
The ones he sang (in Twilight) were "Never Think" and "Let Me Sign".

I love those songs, he sings really good and I love his voice :D

I think you might be talking about the band Dashboard Confessional, they sang a song called 'Stolen'. But I'm not sure. (The song is the slow version)