Vodacom Fibre mess

Vodacom is refusing to terminate my fibre contract with immediate effect. I have had intermittent fibre over the past three weeks in most days with no fibre at all. They have on the same period increased my package but failed to provide a service. They haven't refunded me for downtime I have experienced over the same period. I depend on good quality internet access for my work and a month long notice period without internet will be a nightmare. I have sent emails and called them on numerous times but they are not prepared to provide their side t=of the agreement, therefore it makes sense to part ways immediately. I cant continue to pay for non existent service.