Web africa(vumatel) poor services ****************

Its been a week since upgrading from 40mb line to 100mb line with vumatel (web africa) and im recieving speeds of 50mb via lan and 20mb via wifi on a 100mb line. I have communicated with web africa on numerous occasions and all the say is that my internet speed is correct on there side and that i will receive slow speeds on wifi..so im paying for 100mb line and my phone and other devices all recieve 20-30mb via wifi?????? When i was on 40mb line i did frequently speed test on wifi and got 40mb reading via wifi and lan..now im getting 50-60mb lan and wifi speed on devices is 20-30mb..this is unacceptable as we paying for 100mb..4 tickets have been logged and nobody gets back to resolve the matter. Everytime you have to deal with a new agent at web africa and you have to go through the whole business of explanation and turning on and off your router and speed test and they just say its your wifi device!!!! I believe vumatel with web africa are ******** people from there actual speeds. My wifi speeds and lan speeds has always been more or less the same not 50-60mb difference. ****************!!!!