How do I get my account cancelled?

I contacted 10217 on the 9th and after 45 minutes on hold, I explained that I needed to cancel our business line urgently. I was told to send an email on a letterhead with the directors ID to [Email Removed] I received an acknowledgement from that email address. Today, 13th, I followed up as it was brought to my attention that the line was still operational. After a 39 minute on hold Gugu informed me that the number was still active and gave me *** to use to speak to a manager of that department. The number does not exist and this account is still active. Out telephone line and ADSL needs to be cancelled immediately and I need confirmation that it has been dealt with. Your staff also need to be told not to hand out numbers that do not exist, this is not the first time!