Is it a long time since you got an email from Project-GC last time?
I will try to explain how our flow works. We use Sendgrid as an emailing partner. Whenever an email bounces because of different reasons, they track that. If it seems to be a permanent error (like account doesn't exist), no more emails will be sent to that email address. This is to keep our mail reputation high and not spam those who don't want the emails.
From what I can see regarding your email address, we got a "550 5.1.1 <email@example.com> Recipient not found. <http://x.co/irbounce>" for your email address the 15th December 2014. The system then automatically stopped sending emails to it. Can it be that long since you received one?
In Februari/March we had realized that this was a problem that was coming back here and there. Users didn't understand why they did not receive any emails from us. Usually it's because their mail supplier does weird things.
On the 10th of March we released our first version of a program that handles this. It runs once per day, checks the bounce lists at Sendgrid. If a users email address is listed there, we send a PM at Project-GC informing the user, and also attaching a link to clear the issue (so the mails will be sent again).
Since we added that, I don't think I have seen a single issue regarding this, until now.
The problem here then might be that you got added to the bounce list before the 10th of March. Though I am surprised that you have not then missed them earlier in that case.
I will clear your bounce now.