Trying to cancel a data SIM, all emails returned

Trying to cancel a data sim. All emails are coming back and cannot be delivered. On the cancellation form, ********** is indicated. Can't be delivered ********** also not delivered.

I also gave the completed form to the manager at Woodlands Telkom service center a week ago and nothing has been processed. Is this the norm to ignore these requests? Can this be actioned please? Thanks