I was on vacation when I got the email from Backerkit saying that my coupon was available for getting my printed copy. I looked at it, and then decided that I wanted to deal with it when I got home. Now that I'm home, I am attempting to actually redeem it, but DriveThru is telling me: "INVALID DISCOUNT MAX USES: THE SPECIAL DISCOUNT YOU ARE TRYING TO USE HAS ALREADY BEEN REDEEMED THE MAXIMUM NUMBER OF TIMES ALLOWED." I just looked at it. I didn't use it. Is there any advice on how to proceed? Thank you.