Bad service

In the beginning Vox was good, no intermittent data reception and speed was what I asked for. Now the network is most of the intermittent. I have a 50/50mbps line but it is running most of the time below 40mbps. I have complained about it. Then they do a setting and it work again. A while after that it is slow again and loosing network. I understand now why there are so many bad reviews. I am seriously thinking of changing to another network provider.