Email from comcast about copyright infringement?

so i used vuze. i thought it was ok because other people used it....months later i have two emails(possibly more on the way) for torrents i downloaded via the program. they say my service can be suspended. ive completely deleted vuze and all its components from my computer. but i feel like it doesn't matter because history shows i did download the torrents even if they are deleted now. what should i do? please help?