no feedback from telkom regarding cancellation of a landline

I have been phoning TELKOM to cancel my landline,but they keep on giving me e-mail addresses that doesn't work or is full. I have communicated via social media(facebook) and they have escalated my query but still no feedback...how difficult can it be to cancel a landline????This should be a quick thing for Telkom to do,but seems to me that they are quick giving contracts but takes a lifetime cancelling a simple thing like a landline, meanwhile still charging you..Please if someone can help me,the landline that needs to be cancelled is ***...I even know the number now!!!