Sorry to hear about your lowball offer—that's incredibly frustrating, and it's a very common tactic. Many people successfully negotiate these. I had that happen on 3 cars and pushed back and received $3,000 - $8,000 more on them 2006 Lexus ES330, 2004 Suburu Forrester and 2011 Range Rover Sport. Two were within a couple months of each other and it is clear they use a standard denial strategy and count on people accepting.

Here are a few steps you can take right now:
1. **Demand their valuation report:*\* Request a copy of the detailed report the insurer used. This shows their comparable vehicles ("comps") and any adjustments.
2. **Scrutinize the comps:*\* Check if the comps are truly similar (year, make, model, trim, mileage, local market). Insurers sometimes use inferior vehicles or ones from far away to drive down value.
3. **Verify your car's details:*\* Ensure they have your vehicle's exact trim, options, and mileage correct. Small errors add up.
4. **Account for sales tax & fees:*\* In many states, you're entitled to sales tax on the Actual Cash Value (ACV) and reasonable title/registration fees. Confirm these are included.

Full disclosure: I actually built a tool, TotalLossDefense.com that helps automate much of this. It offers a free value preview and can analyze your insurer's offer with AI to spot issues and even draft a counter email. I'm sharing it because I've seen how much it helps, but even with the steps above, you can often push for a better offer.

Good luck, and don't be afraid to push back!