Cancelling a Vodacom contract

I have 8 contracts with Vodacom. My one specific phone contract ended in August 2018, I have phoned since the end of October to cancel my contact yet a debit order went off on 1 Nov 2018. Again I phoned to cancel yet 1 Dec 2018 a debit order went off. I went into the store on numerous occasions only to be told they can't help. I made my last phone call on 10 Dec 2018 explaining that I'm fed up of phoning, even going into my bank instructing them to stop the debit order and yes, another debit order went off on 1 Jan 2018. This is exceptionally frustrating and unacceptable. Vodacom constantly reassures me that no more money will be withdrawn from my account and month to month they guarantee me that the contact had been cancelled yet it runs endlessly. Ridiculously ***********! Stay away from Vodacom.