Can someone use my isp address to download torrents?

Someone downloaded torrents (of Spongebob Squarepants!) using my ISP address and I am getting DMCA complaints. My network has WEP security. How can this be happening? (And I am positive it did not come from someone in the house.) I use a Netgear router and have three Macs on my network.

Yes, it is possible because if some one hacks your connection and to make it secure all you have to do is to make your connection secure using some tips which I am going to show you in a link. http://goo.gl/hp6uIa

Hello,
You can dowload U torrent directly from Google search.I am having internet issue in ghatkopar area.My society internet is worst
https://www.mumbaipropertyhub.in/projects/aaradhya-saphalya-ghatkopar