You filed an insurance claim with Allstate their driver hit your vehicle however Allstate claims that they can not find the driver to dispute the claim?

You still could pursued the claim under the vehicle. If the vehicle that hit your is being insured by Allstate Insurance, you should be able to set up the claim under that vehicle. Allstate might try to denied your claim based on unscheduled driver but they might get your car fixed with no question ask if you have a police/accident report.