Telkom issue

On the 17th of April 2018, I cancelled my Service from Telkom. On the 29th May 2018 I went to Veronica Mkhabela at Telkom Keywest to confirm cancellation, but my account was still active. She kindley forwarded my documents to Siphosesu Mtana (Fixed Retention Escalation). In August 2018 I received invoices stating that I was reconnected. I then went back to Telkom at Keywest and spoke to the (MD) Deborah Mokgosi who also kindly assisted me and forwarded my documents Cancellation Escalation and said Telkom will need to backdate my invoice. However I have received another invoice with service fees for September 2018. How is it Possible?