Otaku box question for card collectors and the certificate site

My girlfriend is into all the anime stuff and she keeps taking about the otaku box but has been hesitant to order it. I ordered her the waifu cards collection that was announce a few month ago since she’s big on collectors cards. She loves them but we didn’t know that apparently one card you can only get with the actual otaku box subscription for another $5.

She’s still hesitant on the getting the box but considering it now. The back of the last collectors certificate she got says if you upgrade in 7 days of receiving the cards you can get what you missed from last month. The problem is the QR code goes to a blank page that says otaku box and nothing else on it. So she can’t even try to upgrade. Does anyone know a way to fix this or is there a way to order the cards on the site to complete the set for her that we are just not seeing? As of right now they are cards 11 and 22 of 44.