[shmde]

Did you import the copyrighted material from someplace else ? The base link + key was given to you by somebody else ? If YES then copyright holder got hold of the base link and notified mega. This is common.

OR

You uploaded copyrighted material to your own computer to your own cloud, downloaded it and the file got taken down ? This is not possible. If yes then I am in trouble.

[DoItToMe81]

Most likely the former. It was a while ago and I barely recall how it happened.