Unknown contract

Upgraded the contract to Samsung S9 which was delivered. Then noticed when they debit that instead of R500 they debited R800. I decided to leave the deduction thinking that its maybe some additional charged. Next month they debited twice the R800 and that's when I called Vodacom in March 2019. They told me that I have three contracts with them which I disputed. I was requested to send ID copy, affidavit and proof of residence which was send by email. The deduction still continue and keep on calling Vodacom and they tell me that they cannot cancel since the contract is in existence. I should pay for something I do not use or know. I only have one contract with Vodacom for Samsung s9 not the other two. Vodacom to stop debiting my account and cancel the other two contracts which I do not know.