Answer: Gone astray
Go astray means when something fails to arrive where it should, e.g. "I don't understand how my e-mail went astray".
There is an English proverb "Better to ask the way than go astray".
If you are a bit untidy like me, a lot of things tend to "go astray". They are not actually lost as they might still appear one day :-)
However, if you lead someone astray, it means you influence someone in a negative way or lead them in the wrong direction, e.g. She was led astray by her addiction.