Vox telecommunications - Poor service, overcharging

I have cancelled one of two services and requested an upgrade of the 2nd service. These requests were submitted in June 2020. To-date neither has been resolved despite many phone calls and emails. Management appear indifferent in trying to resolve the matter. As regards the upgrade service, Vox has charged for this service yet not delivered the upgraded service. Where credits need to be passed these have not been passed.