Denying the claim is typical insurance action these days. So are lawsuits. It's getting so they deny all large claims as a matter of form. And you may have to sue them.
when i worked in a auto claims office (i was not an adjustor, tho), there were databases of reasonable car values, car repair costs, and injury costs so a settlement offer was based on that and of course many insureds thought the offer was lowball and then they got a lawyer and it was up to their lawyer and our lawyer to negotiate a settlement or in rare cases have to take it to court to reach a settlement.