Most likely you have received a flag from the Steemit Defense League. Refer here for more information: https://steemit.com/flag/@guiltyparties/the-flag-ring

Now unto your question, if you mute someone that user can still see your profile and posts however you as the one who initiated the mute can no longer see his/her post or comments.

Because Steem Platforms are decentralized, there is no way to restrict them from ever interacting with you. What most Steem Platforms do is to hide the mutee's post/comment in the UI-level.