Incorrect debits and charges

I was called by marketing representative of Vodacom to sell me a package with a tablet. When I opened it (after it was delivered after I left for holiday and specifically said I wouldn't be interested if it was delivered after), I decided I didn't want it (which I had a right to do) and asked Vodacom to collect it. After many calls and arguments with Vodacom threatening to list me on a credit bureau if I didn't pay, they eventually agreed to collect the item. After numerous phone calls and over a year later, Vodacom is continuing to debit my account even though they collected the device and I don't have a contract with them. Despite all attempts to sort this out, nobody at Vodacom has resolved this for me, stop debiting my account and refund the debits up to now.