Poor service

On 28 August 2017, I submitted a cancellation request for my landline number as well as my smart broadband wireless 20g package, up to today, my cancellation request has not yet been finalised, however, I am receiving monthly invoices to settle and the outstanding amount is just accruing. I have phoned numerous times, every time I am asked to resend the original email, every time I am promised that the matter will be escalated, etc however nothing is being done regarding my cancellation request.