Telkom Worse service

I'm so disappointed in telkoms service. My mother has been receiving no service on the wifi since last year. One month it works and then it doesn't. On March 4th she contacted them and they restored it the 7th. The 13th of March it was down again. Everytime she contacted them she just got a new case number. All the while they want to collect their money every month and we received no wifi service. Now she wants to cancel the contract they claiming it's breach of contract yet. Yet she's been charged for no service. Can anyone advise a way to go forward as this disgusting service to us as clients.