Bad service-request to cancel not processed.

I took a contact with Cell C in May 2016 for 24 months. I called the retentions department in March 2018 to inform them that I do not wish to have the contact continue beyond May 2018. Mfundo Tshabalala confirmed that my request to cancel would be processed. to my surprise I was still being billed on 01/06/2018 and when I called again on 06/06/2018 Phumelele Nkosi told me that there was no notice to cancel noted on the system and because I could not remember who is spoke to she would not assist and said the contact would only be cancelled from 06/07/2018. Today is 24/08/2018 and I have just had a debit go off on my account from Cell C. I have called again to speak to Mfundo and he basically told me that although I called in March and he failed to document or process my request he can't assist me as the line was still open. He even refused to let me speak to a manager stating his manager will share the same views as him on this matter. I called in time to give notice but now I've had to spend over 25minutes with my airtime speaking to a person who won't take responsibility for not doing what was requested of him in March already!