Start sending them emails about the pairs and they'll get to fixing it. I've done so myself in the past to make them actually aware, and it doesn't take them too long to fix things shortly after.
I did actually get a bit of an answer from them regarding downtime once: they mentioned it was automated and sometimes they aren't really aware since they think they're waiting for the coin developers to contact them about network changes.
Okay, might have to try something like that then. Would be nice to be able to deposit some HBD to Bittrex again! :)