More bills but service cancelled

May I ask why I am still receiving outstanding invoices for March!? from Telkom when a request for cancellation of services was done on the 27 January 2020.

Invoices for February 2020 (fixed voice service) which is due in by the end of March. Was the cancellation request not sent through in January for goodness sake.

Why am I still being billed if the service was cancelled and I have not used the line since around 26 January 2020.

I am aware of the 30 day period and I have already paid of what I assumed to be the last invoice.

Please can you guys clarify as I am under the assumption my line has been cancelled.