I dont want Insurance and i want my January 2020 airtime back

I have a Vodacom contract I***-6 I was in Limpopo in December 2019 where I cold not use my phone because of very poor connection. My monthly airtime was successfully loaded on the 1st January 2020 as usual and I never used it because of the mentioned reasons but how ever the airtime diapered.When I came back to JHB on the 6th I contacted customer service regarding the matter and she told me I used internet I asked for the itemized billing in proving her statement but she refused.

Secondly I phone to cancel my insurance in November 27 2019 and I was told December 2019 will be my last debit as I must pay in arears but I have been debited in again to date January 2020 I decided to exclude the R255.00 for insurance on my account. Till today I'm still being billed for the insurance and it result in the account being overdue and the consultants are phoning me everyday telling me I'm liable for the overdue amount. Please help me get rid of this unwanted insurance cover as Vodacom is filing me as a customer.