When I first got Verizon FIOS, it was working fine, fast speeds (on both 5ghz and 2.4ghz), and for some reason as of late, I literally cannot connect to the 5ghz wifi, it has been in the same place that is has been forever, it doesn't work on any devices (phones, PCs, consoles, etc). I tried renting the extender, but there's no light on the coaxial signal and it just doesn't work.
Once again, it has been in the same place since i got it and now its acting up, I tried rebooting, resetting the router system, etc. And it's not like the signal is low or anything, I can connect to it, but when I do, i can't go on any sites.
Sometimes, I am able to connect to it and it works, but after 5 minutes, it starts to buffer, lag, then shutdown.
That Quantum router has bad wifi as if you google it will see others share your issue.
verizon is at present updating there Quantum Gateway Router which may or may not fix your issues.
however the best scienerio is to purchase a better router either to use as a access point for superior wifi (make sure it has external antennas) and it will more than fix that wifi issue. Of course it could just be a bad router, in which case you could call and ask for a replacement.
you did not say if you have tv as well? If you do and you use your own router you will need a MOCA adapter and that should help with tv connection for video on demand and the channel guide.