Poor service

I have a problem with internet speed. I am receiving 20/10 instead of 50/42 that I am paying for. I had people from Vumatel coming to me. All they did was blame Webafrica for not telling them that my line was upgraded 1 July 2021. Webafrica again blames Vumatel. I was contacted by Webafrica on 10 February with a fault number, 50252 that said that the fault will be fixed in 24/48 hours. Again on 14 February after I requested feedback I got the same answer. It is now a week later and still nothing. I do not know who the guilty party is.