I did accept my claim, though I was a bit late to do so since I was never notified that I needed to, and because accessing the instawallet.com domain without the www stopped working so every time I tried to check on my wallet it looked to me like Instawallet had gone offline.
I message Boussac a couple days ago, so hopefully he responds.
Thanks for the tip - I have not heard back either, but I completely missed payment acceptance since there was no notice to do so.