Unless the police turned up at the time of the crash and made a note of who was at the scene, such as the driver, passengers, then she can't say it was a passenger using her phone if she was on her own. If you don't get the police involved at the scene, it's your word against hers. You pulled out, so it's your fault!
IF she wasn't using her phone, yes she might have swerved - but she may have swerved across into the opposite lane, she might have run over a pedestrian, there's a million possible outcomes - the fact is THIS one has happened and you have to just accept it.