Metrofibre - Disgusting service

Our problems started about plus minus two half three months ago, with metrofiber, were we had no previous problems at all untill they did a urgent upgrade in the area.
I have a 50up and a 50down line with a 8 user or connection. Our contract is with Telkom meaning our router is a Telkom router but the box and cabling and all work carried out was done by metrofiber. But Telkom is our ISP so since Metrofiber URGENT upgrade in the area our service (connection )speed has been disgusting sometimes non existing I have phoned emailed Metrofiber tickets get open, the matter does not get resolved majority of the time I don't even get contacted the ticket just gets closed. we have 3 TV in the house but we can't watch the 3 TV at once, or at one giving time, we used to be able to I am sick and tired of paying for a service when I do phone and fight or if I may get a response on a email I get referred back to my ISP , I have taken the router back to get configured I have bought a new lan cable Telkom our ISP Metrofiber needs to come out and sort the problem out as it is their box, which I agree but Metrofiber says it's our ISP problem, but we did not have any issues with signal before Metrofiber did their urgent upgrade in the area 2 half 3 months ago now every day and evening I must struggle and stare at a blank TV and pay for a service that I am not getting fully.