Hypocritical to say? Maybe - I've blocked Zac for a period before but it got the message across and I explained why by the end of it. Still, this has caused me to think. I'm not best pleased with this circumstance but I'd rather be patient and let it unravel as it's meant to.
Update: since posting this they've appeared back on my AIM list. With luck I'll talk to them later, see if I can work out what happened. Chances are they just didn't feel like talking. But at least this seems pretty much resolved. And at a perfect time too, I'm just off to work.