I'm having the same problem. I had originally 1-3 Mbps (Oct 2008 - Jan 2012). It used to work fine but then the speed seems to be slowing down as years passed by, I was getting less than 1Mbps most of the time so I upgraded to 3-7Mbps with 2 years holding period (Jan 2012 to Jan 2014). From Jan 2012 to Nov. 2012 it was fine, then starting Dec. 2012, the internet started to slow down at night. I'm getting 6-7Mbps during daytime and until around 9pm, then the internet slows down to less than 1Mbps after 9pm. Then starting mid January 2013, the situation seems to get worst, the internet slows down starting around 7pm, and then on the 3rd wk of January, the internet started to slow down as early as 5pm.
I've contacted the customer service twice. First, the person who attended remotely accessed my computer and after more than 15 minutes trying to find fault at my computer, wiring, set-up or wireless router (instead of the verizon network), he realized he doesn't have any excuses and instead instructed me to hard reset the modem. I told him that if I hard reset the modem, he will be disconnected to my computer. He said, "that's fine, I will call you you to give instruction on how to set-up the modem". After I have hard reset the modem, he never called up and I was left all by myself figuring out how to set-up the modem. I've contacted the customer service the 2nd time, a different person attended and exactly the same thing happened, the guy instructed me to hard reset the modem but never called up after he got disconnected. I guess this is their expertise, how to rudely leave the communication once they figure out that they can't resolve the problem.
Once the 2 years holding period is over, I will change to other internet provider and will never switch back to verizon again. I will never ever recommend verizon to my friends and will share them my experience with verizon.