Why are some channels removed?

[JayMach]

I'm brand new here and brand new to this hobby. I was just wondering why some channels are removed?
Since getting my donation and my own Avov box, I've noticed I don't have access to some channels that my father has (he's with a other service). They're international channels. I noticed they were once available in the master list when I look back.

[dells]

that's just the way it is, channels come and go, what's working today might not be tomorrow and vice versa