Paying for 100Mbps getting 20Mbps

Hi,

My problem is that I am paying for a 100Mbps capped Fibre. On average my line speed is 20Mbps on a good day maybe 50Mbps and on bad days (which happens most often) 0.5Mbps.

My fibre line slows down to a point where my Youtube videos buffer.

I have phoned Afrihost, spoken to them on WhatsApp and emailed to no avail. I understand that Frogfoot manages the line etc, but my ISP is Afrishost and I expect them to sort it out, however, every time I log the query I am asked for the same details, a called gets logged and that is where it stops.

What must I do to have this sorted out, I have been a loyal customer of Afrihost and their service has always been good up until now.