Internet up and down all day, Comcast saying "No problems!"

I am very frustrated.  I have restarted my modem AND my computer.  Cable connections are fine.  Service has cutting in and out/intermittently very slow all day.  I checked for power outages in my zip code, and the outage map is telling me there are none reported in my area, but there are outages in the zip codes all around mine.  This is a common scenario when my internet service is cruddy.  I tried calling to report it, but after I went through the whole voice menu I got a recording telling me to try the website, and then got disconnected.  Any suggestions for how to get Comcast to acknowledge this or do something about it?