Putrid service from Datalink SA

For 2 years just before the COVID 19 pandemic, we have been complaining about our phone lines that isnt working properly, we had techs come out to check and change whatever the issue was and we are still experiencing the same issues. We have contacted them countless times and awaiting a superior to contact us, but nobody seems to budge or help get this sorted out. We need to be refunded for the time it has not been fully operational the way we were promised when we signed the contract