Parking door was open – others drives on door

Hello, my girlfriend has opened the door in the parking lot of a supermarket chain and at that moment a car has driven to the empty parking space next to it and of course rolled against the door. At the car of my girlfriend you can see nothing, and at the vehicle of the woman who drove into the parking space only a slight scratch (was or is an ancient BMW with 100 scratches and bumps) – my friend has said naturally in the excitement that it is her fault and thus the ladies have addresses a The lady also said that it’s not so wild – and she probably doesn’t want to do anything anyway. So after 4 weeks we get a letter from an insurance broker (take it to that is her husband or an acquaintance). With BMW reviews – 4 pages long – net 890 euros. We should please transfer the money to the account XXX. (where I ask myself if the old BMW is still 900 euros worth) Hmmm what do you do now? I find the debt question is not clearly clarified. – even if my girlfriend has to admit the guilt at the beginning. If I now report this to the insurance it may be that this increases the contributions etc. – Attorney because of this sum brings me also nothing. Maybe someone has a good suggestion – thank you