Yes, normally you can dispute the settlement amount your insurance company. If you cannot negotiate the settlement to what you believe is a fair amount then you will need to follow the terms of your policy to figure out a settlement using such methods as arbitration or mediation.

It depends upon state laws and your insurance policy terms what you can do in your situation. In general if you are unhappy with your insurance company’s settlement offer you continue to negotiate with them using information on what the actual cash value of your vehicle would be according to blue book, local car sales, etc. If you cannot come to an agreement on your own the terms of your policy (or state insurance laws) may allow you to seek mediation or arbitration. Look at the arbitration/disagreement clause in your auto policy.

For example in California their Department of Insurance describes their state's mediation program. The DOI notes that mediation is a process by which you and the insurance company submit your dispute to a neutral third party (the mediator) that works with both of you to reach a settlement of the dispute. The mediator has no power to impose an agreement on you; only you can decide to settle your case. One of the purposes of mediation is to give you the opportunity to tell your insurance company your perspective on the dispute. Mediation is effective in joint session. Within the context of the joint session, the mediator will usually meet first with both parties and then meet with each party privately to resolve the issue.

The Texas Department of Insurance states that if your insurance company totals your car but you cannot reach an agreement on the amount to be paid, you can demand an appraisal. Appraisal allows you and the company to hire separate damage appraisers. The two appraisers choose a third appraiser to act as an umpire. The appraisers then review your claim, and the umpire rules on any disagreements. The appraisal decision is binding, but only as to the amount of the loss. If there is a dispute over what is covered, you can still pursue a settlement of the coverage issue after the appraisal takes place. You are required to pay for your appraiser and half of the umpire's costs.

Appraisal is available only in disputes between you and your insurance company. It is not available if the other driver was at fault and you disagree with his or her company's offer.

To find out what you can do about your situation try contacting your state’s insurance regulatory body as well as reading through your policy's terms and clauses that might explain what to do in case of a disagreement during settlement negotiations.