So were we! It's sad when sites suddenly close without warning, and there can be all kinds of reasons for that; health, human error, bad decision making, the inability to keep it going for wahtever reason, etc.
We won't speculate on the reasons why here because we don't know the "why" in this case.

The important "why" to know is that you need to spend your time and advertising dollars with advertising sites that are growing, active, innovative, and that will present your ads in a way that gives them the best possible opportunity for success. Ad sites managed by dedicated professionals, well established admins with a track record for success!

Here are some sites that meet those qualifications!