MTN insurance company: Admyntec deducts ******** payments

I had mobile insurance with MTN and Admyntec services are the administrates, I have cancelled my insurance in August 2025 and received written confirmation on 20 August 2024 that it has been cancelled. Then they still deducted for Sep, Oct and Nov 2025 of which I brought it to their attention but till date have not received a refund for the months that were deducted after cancellation. I have been following up since Nov 2025 to date, sending emails twice a week and still no response on the refund.