Vodacom dropped my fibre speed to 10mbs even though I pay for 50mbs and have been doing so for years

Vodacom dropped my fibre speed to 10mbs even though I pay for 50mbs and have been doing so for years. When I called them, they say say it’s automated and not their fault. They are rude, and now want to increase my bill and lower my speed. The call centre lady repeatedly cut me off when I tried to explain. Worst customer service ever I have been waiting for 10 days and they still bill me for 50mbs while providing 10mbs. They keep calling to say they will fix it but nothing happens. Ntombi has promised with zero delivery.