Vodacom charging for a headset contract after cancellation

I had a 24 months iphone contract with Vodacom form March 2017 . This year 2019 in June I called Vodacom to cancel the contract but I was advised to rather move to an option where I will only get R55 airtime every month WITHOUT a new phone ! BUT Vodacom has been charging me R400 after I moved to this new R55 airtime contract. On my statement it reads that I am paying for a headset. The headset that I have finished paying for . Vodacom are ****** who continue to debit from their loyal customers even when the contract has ended and has been canceled.

I have called to dispute this irritating and costly fault that they made but I am not getting any help . They had claimed they logged a call with ref number : *** but that’s where it ended .

I want Vodacom to stop debiting this R400 and I demand them to refund me for the past 4 months they have been debiting on my account. This is ridiculous and it’s a ***** for such a big company to rob their customers. It’s is so disgusting and disappointing. I even have a copy of my 24 months contract. Vodacom is nuisance !!!!! I demand my Money back