I know you already reset your modem/router but for anyone reading this post in the future, know this:
If your modem/router was supplied by your ISP, they may have set up specialized instructions (DNS addesses, system access passwords, etc) in your modem/router and if you reset to factory defaults you will loose them and potentially loose your ability to connect to the internet at all. Since you were never in there to record the proper settings you do not know how to reset them even if you do now have access.
Contact your ISP.