My Modem Has Been Reset
If a support representative has asked you to reset your modem (or you just felt like pressing random buttons) you'll need to re-configure the modem again. When the modem first gets send out to you, it'll be preconfigured with all the required settings - which get lost after a factory reset.
You'll need to contact a support rep to get your DSL username and password, as this is separate from your WiFi password.