Pathetic service from Vox

I am so frustrated struggling with Vox WRT an account that is supposedly overdue. I gave notice on my package I had with them and chose to continue only the unlimited calls package at the end of the agreement. For some reason the cancellation period has not been honoured as I paid for the pro package for the month on October and then was told that my package was changed at the end of September already?! What happened to the notice period?