Incompetence and THEFT

On 13/11/2021 we cancelled 3 data lines with MTN, as we have upgraded to new devices with another service provider. A confirmation email was received, as well as a few emails confirming the reason for cancellation and then an email to the "TEAM" to cancel the lines. Yet ever since, they have continued to deduct the money from our account, and email upon email, but nothing - this is theft