How Do I Know What I

The first time I sold a photo, I only knew it because someone congratulated me on it. But I got no notice from FAA until they eventually sent me a check. The next time, I only found out because someone I knew bought some photos, and she told me she had done so. Otherwise I would not have known.

I understand that the sale isn't final until 30 days have passed, but I would like to know what has sold when it sells. There has got to be a way to find that out. What is it?