Services keep on running after cancelation - still receive accounts

We had two lines with ADT Fidelity, one was cancelled last year 2020 ELK00025 the alarm was not in a working order we cancelled the line, in 2021 we noticed it was not cancelled yet and contacted fidelity to cancel the service because they never cancelled it they gave a retention discount the rest over was paid and the account was closed. On the 19th of August 2021 we send an email to close the second account ELK00024 and again we still receive invoices, again fidelity was contacted and we received a email that they will come and take out all equipment and the service will be cancelled. But still we receive invoices for both accounts. Both accounts was paid in full when we requested to stop the service now again there is a balance due above R1000 per account, this is so unprofessional and bad service. I ask to go back to both accounts and sort this matter out and clear both accounts.