Vodacom you are negatively impacting my credit score for NO reason

I am exhausted by the number of collections agencies calling me to collect on a contract I cancelled in Feb 2018! Nearly three years of harassment! Each time I have patiently forwarded proof of emails and payment and signed cancellations quote to the relevant collections agent . Only to be called a few months later by a new one. I am typing this while standing in a Vodacom store in a mall where the agent trying to help me also seems to be getting the run around by your retentions department who clearly just didn't cancel my contract when they received proof of my settlement payment three years ago. I've had to take time away from work to come to a Vodacom office to try get this sorted. And to top it off this is probably affecting my credit rating. Completely unacceptable. Apparently the account is showing is cancelled at retentions team due to non payment and only accounts can help us.. but this is NOT a non payment issue. I have all the evidence of having paid the quoted settlement amount. WHY are collections agencies calling me !!!.?? Please call me to resolve this *** or email ***. This is honestly the worst and most costly customer experience I've ever had Vodacom!!!