Cession Cancellation Letter

I had a home loan with FNB which was paid up and the account closed on 26 July 2021. Since than, FNB has refunded me any excess amounts owed to me, but they have not provided any formal communication to indicate the account is closed, nor provided a cession letter which allows me to release my life insurance policy.

I have sent emails to them (***, ***) and I am not getting any response, or at least some form of automatic email response to acknowledge receipt (like other proper business' would have in place).

I require this letter urgently to stop a life insurance policy as I have moved to London, and this is the last matter that needs resolution. I require a letter indicating that FNB no longer have an interest in the policy and that Liberty Life can remove the cession. This lack of response, is losing me money, as I have to pay premiums on a life insurance policy to cover a bond which no longer exists!