Poor fibre service

I am very frustrated with my fibre services from Vodacom. I have to phone in weekly as the fibre line keeps dropping, Further to this, I am paying for 100mbs, uncapped, and when I test it, it only runs on 30 - 40mbs. I get a lot of buffering. when I call in, it takes a long time with disconnect and numbers and still, it does not work properly. I have asked to speak to a senior person, or a number where I can complain, but to no avail. I have 7 contracts with Vodacom and I have been with them for nearly 30 years, I have never missed a payment (on average R10k per month). I am terribly dissatisfied with their service. I have asked who I can speak to, to cancel my contract, but they cannot assist, because that is only the helpline. I have responded to their survey that they want us to do at the end of every call. I have given them the worse scores and still, they did not give me a callback or query why I gave them such a week revue.