Vox unreliable wifi

We have been with Vox for 2+years now and have not had 1 solid month where our wifi is up to what we were promised. We have contacted them.and always had to wait for days for them to come out furthermore they always say that we have too many users. How can a family of 4 be too many users for a 100 Mbs line. All I can advise other people in need of wifi is to not use Vox....definitely unreliable