Just got Gigabit internet a month ago and worked great until last week. Speed were always in the 600-900 ranges which is fine and dandy but now it is a joke.
120/5 for a week and nothing the techs on the phone could do except scratch their heads. Tomorrow someone comes out to probably just unplug things and scratch his head too.
I can't really believe this is even possible to happen let alone can't be fixed quickly remotely.
First off simply unplug everything from your network. All computers, cell phones,tablets, printers, or anything connected to your router.
then go in and turn off the router. Wait a few minutes then plug that back in.
let it fully boot up so nothing is flashing.
then add each device back on your network and then connect a computer via ethernet to the router and then do a speed test here: https://www.verizon.com/SpeedTest/instantinternet.aspx
see if the speed has improved.
The tech will do this but beat them to it.
you can have them line test from their office and if the speed is showing ok then it would be something on your network. Have them check your router as well.
By the way this is in the wrong forum. High speed Internet actuall means DSL, which by current standards is not really high speed.
Previous poster gave good hints of what should diagnose and restore your FIOS Internet speed.