Diminished Value question

My 2014 TL was rear-ended and had $16,000 in damages. The insurance company refused to total it so now I have a bad Carfax car.

Can anyone shed some light on how to find a legit diminished value appraiser? I have been looking for a few days but every one I've investigated has horrendous reviews in ripoff report, BBB, etc.

Thank you.