Can an insurance company deny a claim if it has paid a claim three times for a roof to be fixed and it was not fixed And will the new insurance company fix a roof after being with them only 3 months?

Yes, they can deny the claim. If a loss payout was already issued by an insurance company, it was the insureds responsibility to make the repairs with the funds provided. The company is not required to pay the same claim twice.

If the insured fails to make the repairs you can not seek those same funds a second time.

Also bear in mind the following

1. Your homeowners insurance policy is a term policy, usually a one year term. So your new insurance company would have no obligation to pay for claims for previous damage nor un-repaired damages that arose before the policy started.

2. Your Home insurance company also does not provide coverage for poor workmanship or quality on the part of your roofing contractor. This is why one should always hire a professional roofer and verify the the contractor has Insurance before allowing the work to proceed. If the roofer did a poor job resulting in failure of the roof or materials you will need to file claim against the contractors general liability completed operations insurance policy because the homeowners insurance company does not have to pay again for the same repairs. It is up to the homeowner to hire a qualified contractor.