Laptop contract

I had a laptop contract with vodacom which ended this year April and I called the cancelations dept to cancel my contract I was informed that I will be debited again in May since I canceled late and I was ok with that, June and July was debited again I called them explaining that I did cancel the contract and they let me know that my account was not closed like they promised to so I asked to speak to the customer service manager that heard my complaint and assured me that this time they will close the account as they can see that the Sim card was canceled and they gave the number to sum1 else.i then asked the lady since calls are recorded can she check my calls investigate and get back to me as I explained that I canceled the contract when it expired in April . Aug they debited me and I reversed the debit order and called them and yes they promised me my account was closed and did Not know why I was debited, today I get a call from debt collectors saying my account was handed over as I'm in arrears, VODACOM PLS INVESTIGATE THIS IM FED UP NOW.