Telkom won't cancel my telephone line

Telkom, I gave you notice on the 10/11/2017 to cancel both my ADSL line as well as my prepaid telephone line effective 01/12/2017. Why are you still sending me accounts? I am not paying a telephone line rental fee for December 2017 and I am certainly not paying a telephone line rental for January 2018. Adjust your records accordingly and with immediate effect!!!!!