Total Loss Value too HIGH?

I was involved in an accident that was not my fault. Both drivers have the same insurance company. The cost of repairs is estimated at about $7000. I was told by the adjuster that the car would be totaled at 70% of ACV. It is a 2003 Jeep Grand Cherokee Laredo 4wd with 116000miles in average condition at best. (Needs tires yesterday and $4500 in previous body work, wear and stains on interior). KBB, Edmunds, and NADA have the value at around $8k-$9k so they sent me to total loss dept. Total loss told me it was totaled and that I had 5 days of rental car left and made arrangements to pick up the vehicle. The next evening (after Ihave arracnged financing and started looking for new car) they called back and said never mind we looked at the wrong file, your vehicle is valued at $11,900. I was shocked. I want the car totaled. Gap insurance will cover me whatever they pay but $11900 is ridiculous. How do I argue that they have overvalued the vehicle? I paid $12500 over a year ago from a dealer in excellent condition, with new tires, and 62000 miles.