Bad Vumatel Service

My fibre has been installed 2 weeks ago. Instead of being happy. I realised Vumatel is juat as bad as Openserve. Infact I am thinking to go back to Openserve. I am paying for a 20mg line. We cannot watch a movie without rhe movie stopping and and loading. Stopping and loading. This happena with just 1 smart tv connected to the internet and 2 cell phones via wifi. NO OTHER devices. My sevices provider has twice logged a call with vumatel and both times vumatel has closed the calls. My line is unstable when I run a speed test i get results between 12 and 22. Vumatel says there is nothing wrong. I spoke with a most arrogant Manger at Vumatel. According to him my service provider must sens a technician out to see what the problem is. I told him that Vumatel can come and remove there devices off my property. He said it is my choice and it can be arranges. Isp - 74041 -25/3/19 and isp -74568 27/3/19. I went so far as to changing my lan cables. Nothing changed. Still bad! Only thing changed is my bank account!!!