Car accident

Hi
Last Thursday I slid into back off a bus no damage to bus. But damage to passenger side. I have been in touch  with insurance but waiting for them to ring back . Car is driveable. But it's 2011 Peugeot 107 . I know garages always put extra on top of the know it's a insurance job   I'm scared of insurance writing it off.  I'm wondering if can cancel claim and pay for it to be done my self . Because I've been reading up that if they class as a write off do they keep car .