Volvo: Rear-ending a Volvo, vovlo, warning device

Question
QUESTION: I was sitting at a red light and rolled forward to sit for another red light (only advancing about 15ft) when my foot slipped off the brake, causing me to bump the Vovlo in front of me.  We examined the vehicles and there was absolutely no damage.  Now she is stating that it is going to cost her $880 and three days for a Volvo recommended mechanic to "repair" something that is under the bumper.  Do you know what the possibilities could be?  I was rolling no more than 3mph and 15ft forward.

ANSWER: Ronda,
It sounds like a bait and wait. About all you can do is call the insureance and see what help they can be. Since I do not know the model and year of the car and what options were on it I do not know what could need replacing. Maybe a rear back up detector warning device?

---------- FOLLOW-UP ----------

QUESTION: It was a four door sedan that was probably 2003 or newer. I do not know if this helps.  The driver mentioned that she had just been rear ended a couple of weeks ago and had a new fiberglass-plastic (?) bumper put on.  
 I hope the additional information helped to clarify what the potential problems could be :). I can not imagine how a repair could take three days?!
Thank you for your time and assistance

Answer
Ronda,
Since it is a plastic style bumper assemble there is the possibility that the attaching bracket(s) are broken. If the rear bumper needs to be removed and some prep work like painting sanding drying time etc. Maybe three days are what is needed.