Bad support and service delivery

I have been having issues every week since my installation has been done. I am off once a week due to Fred Fibre for a minimum of 24 hours up to about 3 days at a time. When phoning support the phone either just rings or is always engaged. We have sent multiple emails with no responses. We are at the verge of changing service providers if this does not stop. We are experiencing a loss of income due to all these disruptions.