When you log onto a Virtual Private Network (such as IPVanish) nobody can trace you with the exception of the VPN company. Since all of your traffic is encrypted, not even your ISP can trace you; all they see is a stream of encrypted data moving between you and your VPN server.
If you request a file from a web server on the internet, the VPN fetches it for you, encrypts it, and sends it to you. The owner of the web server doesn’t know who you are because he only sees the IP address of the VPN server. So, if he wanted to track you down, his only option is to pressure your VPN company to reveal your identity.
VPNs were invented so that corporate employees could log into the company network from home, or while traveling. So VPNs are very secure. However, this doesn’t mean that they give you a license to do cyber crime. If you do something that causes a subpena to be served on your VPN company, they will be faced with the choice of ratting you out, or going to jail themselves. Obviously, VPN companies need to follow the law, so use a VPN for privacy rather than crime.