unauthorised insuarence debit, no response from vodacom and finrite

I app**** for cellphone contract with vodacom and I got the phones. A lady later called me selling cellphone insuarence and I told the lady I wont need insuarence. When I am getting my statememts I see a debit order every month for insuarance. I called vodacom several times and they say I must call finriite. When I call finrite they say they dont have my number on the system. I send e mails and no responses. I dont know what else to do now