Billing when account is closed

<p>Hi there</p> <p> </p> <p>I have cancelled my contract but am still receiving invoices for data usage when a) my account is closed and b) the device has been off.</p> <p> </p> <p>I receive different information from everyone who I speak to at Telkom and there is no clarity.</p> <p> </p> <p>I need to escalate this. Please help me.</p>