You can appeal the estimate. Me and my mechanic did this a couple of times when i got into a similar wreck with my old car. Since its and allstate pro shop, the word of the repair guy carries a lot more weight with it. Insurances never want to pay out sometimes and you have to fight them. My exgirlfriend got into a similar situation with her ride and eventually just called her insurance and told them and they got it settled. Her original estimate was 8K in damages, after her insurance got involved the estimate was changed to 9K. She had allstate at the time too.