Mother is deceased and unable to cancel her account

My mother died on 1/1/23. 

We notified Verizon to close her account. Unfortunately my brother had been using her line of credit after she died to buy a phone and tablet is an account manager and got someone to impersonate our dead mother and claim she wasn't dead and get it reactivated and removed us as the other account manager. 

We have the death certificate and even brought it in and got a confirmation that the account would be closed today. 

We were then notified that they told my brother and he just undid it again somehow? 


This is fraud at this point and it goes against the policy I see online. How do I get my brother off of my dead mothers account?