Incompetence and billing despite cancellation

I went into a Telkom Branch in Clearwater Mall to cancel my account and was given a form to fill out with an email address to send the completed form to. I filled this out and sent it through on the 30 April 2018. I have since still been receiving bills and have emailed them again querying this and have now been told that the email address no longer works although this was the information coming from their branch. Complete incompetence and now I have to sit and fight the billed amount due.Still awaiting a response from Telkom.