Poor customer service- Please contact

I cancelled a DSTV smart card in May 2019. Since then I have received an SMS stating the amount is outstanding and the account has been suspended. When I called in the telesales agent insisted it was the Showwmax I need to cancel and would not listen to what I was trying to explain as there are numerous smart cards linked to the same ID number. I asked to then speak to a manger. I was put on hold for 30 min and then told there are no managers around and I should phone back later. This is unacceptable customer service. Please contact Michelle on *** to resolve as I will not hold over and over to speak to a manger.