Allstate Insurance review: The insurance did not meet its obligation

The Allstate insurance co. treated us very unfairly and did not meet its obligation. Please see the following:
1. We had a Landlord Home Insurance for many years from AllState (Self-called "good hands" Co.). We always pay the premium bills on time and before the due date.
2. On June 30, 2021, the rental lease would expire and we decided to move in from July 1st, 2021. So we wanted to change the house insurance policy from Landlord Home to home owner insurance.
3. On June 12th, Yuenlin Li called agent office to switch insurance and paid for the premium for the new policy starting on July 1, 2021. Because the rental lease should end on June 30, 2021, so he told the agent to change the policy starting from 1st of July because the tenants still in the house until 06/30/2021. However the agent changed it on June 12th by mistake without Yuelin Li's knowledge.
4. Jing Tang found the mistake during the claim procedure and asked the agent Sarah to make the correction, at the beginning Sarah agreed to make changes and did not think it is a problem. However Sarah did not make the change to correct the mistake (Possibly she found out that we made some claims).
5. On July 23, 2021 Jing Tang and Yuelin Li called our agent office for correction. The agent Roni agreed to correctly change the effective date to switch from our landlord home insurance to homeowner insurance on July 1, 2021 (the phone call was recorded. We had to do this because the promises were broken by Sarah before). However, this change was later denied by Sarah again despite the legal facts.

Thanks for your help.

Jing Tang and Qiong Tang
Email: [protected]@juno.com