Vodacom making clients to pay for an insurance with no phone

I have a Vodacom cellphone account which I bought a cellphone in 2022. The handset had an insurance and the handset was paid off. I requested that the number be cancelled instead they made a flexible zero. This resulted to a cellphone insurance not to be cancelled. I am still paying for the insurance to-date after numerous attempts to have it cancelled. Literally they owe me about R40 per month since 3 years ago. You are only limited to communicate on phone and no formalized communication is provided ie emails etc. I phoned this year again and received sms of the request and I am expected to pay for insurance that I am.not using. I hope that they will listen or i will have to pursue other options.