Continuous billing of magazine after account close

I called a year ago to stop the monthly subscription of a magazine to my account, a magazine I never received. I however, settled the account then. Then In February 2015 I received an sms saying my account is overdue. I called your CTA office and spoke to Sigera Parker. She confirmed that the subscription was canceled and my account balance was zeroed. She also told me this error on Foschini's part would not be reflected on my credit report. However, I received another sms now in April saying my account is overdue. How hard is it for an organization like yours to not follow through with a consumer's request?