If it was set voice activated it is very possible everything you've done has been broadcast to your games >.< even if you enable push-to-talk, your mic will be on when you or someone else joins a lobby. This can be a split second thing or sometimes even several seconds of open mic. On top of that, sometimes in the course of normal play, a mic set to push-to-talk will randomly go off as if set to voice activated. Seriously -.-
If you set voice chat behavior to Off you won't hear other people speaking either. No mic chat whatsoever. If I want to leave voice chat on I set it to push to talk and then use the mute switch on my mic/headset. Even this has failed me before though so I tend to keep the Recording Devices window open in the background so I can alt tab out occasionally to make sure it's actually muted. Welcome to the wonderful world of PC voice chatting

Edit: Oh.... You're talking about the ORIGIN mic settings. Ok so yeah... The one time my friend and I tried using the Origin voice chat feature it didn't only broadcast our conversation to our origin chat room, it also shared the entire thing with everyone in our DAIMP lobby. If you figure that out.... Let me know :/