turn on the encryption in the torrent client it does work. vpn is great for hiding the fact that you're downloading a torrent or magnet, and the encryption in your torrent client in most cases will keep your isp from seeing what you are downloading.
But it doesn't prevent all other clients from seeing your IP. It's not your ISP who cares what you do, it's the right owner and his law firm. They pretend to be an ordinary peer but in fact it's a monitoring software which logs every client uploading chunks to them. Depending on the country you reside they go to the criminal justice, prosecutor, court or ISP with the logged IP and resolve them to the internet subscriber and that's the point you are busted.