Terrible service provider

I had a WIFi data bundle contract with telkom. Telkom decide to charge me exactly extra R500 for March invoice. When I called the consultant was rude and she explain that I have used more data for the month. However whenever my monthly data is depleted my internet connection is paused. She didn't want to hear me explaining, that what they charging me, it doesn't make sense and she drop the call. Telkom deserve 0 star