Cannot Access Internet

For about a week, my boyfriend and I have been without internet. We rent our home, and in effort to try and restore the connection, my landlord remembered that our house does not actually have Comcast service (that is the internet provider we have), but rather a line is run underground from his dad's house next door to our house and connected to a modem here. We have never had any trouble before. My boyfriend seems to think that there is a modem we can buy that provides its own internet. Is that an option? Does anyone have any potential fixes for the problem? We bought a new router, but it is not solving the problem.

The devices all say they are connected to the router, but none of them can access the internet.

Thanks!!