Paying for a service when it doesn't work

Telkom contacted me in Nov2017 to upgrade from 4MB to 10MB line. I agreed and in Dec 2017 it was realised the exchange can't do 10MB while being internetless for 2 weeks. When I downgraded back to 4MB after many fights over the phone, my internet was back on but running at 1MB. Since then I have complained numerous times where I was promised a technician will come test they will give feedback it has been escalated and so on. To this day I have not had any pleasure from telkom.