It's true that Vanessa worked with Stevie on the album, and that she was heavily influenced by Stevie, but she only sang backing vocals on The One. Don't you think if Stevie did sing backing on all the tracks, it would be credited? And besides we would probably know if Stevie did sing backing vocals cos of her distinct voice.
I don't think Vanessa lied about her own music, I think there was just a language barrier and it you took it out of context.