Vodacom fibre is the worst line and service

In December I've had no fibre for more than 3 weeks. That were sorted. They gave new rooter. Now the new rooter is working when it wants to. Fibre on and of every 15 minutes. From January This issue started and also Going for the 3rd week. They keep on saying they will follow up and the technician will contact me. But it doesn't happen... I can't keep paying for this ridiculous service and bad fibre line and rooter.