Dialers may disconnect your computer from your Internet Service Provider (ISP) and reconnect you to the Internet using an expensive toll or international phone number. Dialers can accrue significant phone charges and can run in the background, hiding their presence. They generally propagate themselves using dialog boxes, various social engineering methods, through scripting errors, or may be delivered with a Trojan horse. The Federal Trade Commission recommends that you dispute the charges with your telephone company and report the incident.