There are two textboxes on the screen to be notified when it becomes available. I first tried the bottom one, and it gave me an "Too many subscribe attempts for this email address. Please try again in about 5 minutes. (#8715)". I tried it a few times after waiting a few minutes, then went back to the first textbox, higher on the page, and that one worked without issue.
I had the same problem, but a different error code number: "Too many subscribe attempts for this email address. Please try again in about 5 minutes. (#8617)". I clicked the Submit button once.
I will say, one time a few years back I needed to get a receipt from a purchase more than 60 days old. I called the local store, and she said "just give me your credit card number and I can lookup your transactions". With just my card number she was able to see every transaction I made with that card (and find my purchase I needed the receipt for). So (at least 3-4 years ago) it was being stored somewhere searchable by people in the back office.