I'm in Canada, so hopefully this info helps anyone outside the States who hopes to get in on the promotion.

My friend down in FL bought 2 bars and had the receipt - perfect picture, all info on it. Her assistant also bought 2 bars and took a pic of the receipt, but this one was missing the date and time. They threw out the receipts before I tried to submit, so I worked with what I had.

I submitted the perfect receipt first near the beginning of the promotion. Got an email saying they had it, would get back to me. It was rejected a couple days later. I opened a case with their customer support and received back a canned reply without any clarification. After reading some other experiences, it seems like having an IP address outside of the States flags your account and your receipt gets rejected, or you get an email where the DLC codes are blank.

I re-submitted the perfect receipt, but now switched to a new email (my old email was actually locked on the submit screen - it said I had submitted a receipt for the day so try tomorrow, even after clearing cookies and even though I had only submitted the once). I used a VPN to place myself down in Florida. I rotated the picture to landscape, so that when I uploaded it the preview showed the receipt in the correct upright position. This worked - got my Tifa theme and the Midgar bangle.

Just to test, I also submitted the imperfect receipt. That was ALSO accepted (again, using VPN and rotating picture). Seems like they're being more lenient now after the initial screw ups at the start of the promo.

TL;DR - Use a VPN if outside the States, make sure receipt is oriented correctly in the preview, date and time purchased may not matter once you've successfully submitted a previous receipt.