Until recently I had several videos saved under Past Broadcasts, but now when I go to my stream it shows nothing. However doing a search for my name shows videos from 2-3 weeks ago that I recorded.
I recorded a stream last night, ending around 10:30PM EST time, which broadcasted fine while Live, however that video does not appear at all on the site, neither on my channel nor in a search for my name. This only seems to have happened within the past ~2 weeks or so as previously I could go to my stream and see several videos under "Past Broadcasts", but now there's nothing.
As you may know (from the drop-down banner and our blog), archiving is now an opt-in feature: http://blog.twitch.tv/2013/09/archiving-to-become-an-opt-in-feature/
After you enable this feature, subsequent archives will be recorded and live from 4-7 days before being deleted.
If you did not have this feature enabled, we did not save any of your broadcasts, thus there are no records for us to recover.
If you use PS4, there is no archiving of PS4 broadcaster per Sony.
You enable archiving for non-PS4 broadcasting via Video settings here: http://www.twitch.tv/settings/videos