this makes me think a padlock sign means they have hidden your profile so that you do not show up in there searches.. and I guess. The fact they did this means they do not want you to contact them meaning match stops you from winking or contacting them

Can you hide being online on match?

On the Match app Tap on the “Profile” icon at the bottom of the screen. Tap on the gear icon at the top of your profile page. Under “Profile Visibility,” select the visibility you would like for your profile: Visible, Hidden, or Private Mode.