Bad service from Telkom - cancelled line

I have just now received a sms from Telkom saying my "account" must be paid before 13/01 while the account due date is 26/01/2018. I phoned Telkom yesterday about this account since I'm still getting charged for a cancelled line A/c No. ********** 20001. This was cancelled on 21/11/2018. I have forwarded the email to the person that helped me at ********** I have paid my one month in advance in the month of December. They keep charging me for the cancelled number. My current account number is ********** 40165. I want action on this immediately.