I Called My Bank (they Provide My Insurance), They Stated That My Mother Removed My Vehicle From My Insurance

I have 2 cars on my insurance policy with usaa. One day out of no where they tried to charge me $900 and I called them. They told me it was because I had 3 payments that's I paid late. I told them that I dont want to renew the policy after this one expires. They said okay.

1 month later I notice my rate is $500 and my mazda 3 is not on my insurance. I called usaa and they said that my mother removed my vehicle. I never authorized this nor did I want my vehicle removed. I only wanted my insurance policy to end with my current policy and that's it. What can I do?