[cvinson]

Happened to me. Worse, competitors started copying my exact Adwords text and headlines as well.

I was able to remove the ads that included our trademark fairly quickly by contacting Google.

For the rest, you just have to start your own campaign against them. Since our own company's keywords are pretty low search competition they are extremely cheap to bid on. When competitors see that you are bidding against them, they might back off (they did in my case).