Unless you are downloading through an anonymous proxy server or some sort of a secured internet tunnel, your provider knows every single site you are visiting and every single file you download (well it is a little bit more complicated than that, but in general this is correct).
FrostWire - it is essentially a BitTorrent client. To download a torrent, you need to download a torrent file first on your computer from somewhere on the Internet. Unless you are doing it through a anonymous proxy, the provider will know you've downloaded that file. The next thing is the provider can see what sort of traffic you are using. BitTorrent's traffic, though masked, can easily be identified as such by your internet provider, although it is impossible to know what exactly you are downloading, anyone can assume that it is the torrent that you had downloaded earlier.
The internet providers keep logs of all of your activity online!