Telkom is unprofessional

I have cancelled my contract on 22 September 2017 but Telkom is still sending me invoices and debiting. I have blocked it from my bank but they changed the reference so that they can debit. i spoken to ********** and she said it will be cancelled, today i have spoken to ********** and she said it was never cancelled and Neo is busy with it. I am so fed up that they don't have complain contact number were i can complain. Neo is handling it, i can't speak to him or her to check the progress. Telkom is *****ing my money because i have cancelled last year. It is not my problem that they are not doing their job.