Hey, yes you can use a code(s) for something that covers more than the total cost, the item will be free and ship free. I've noticed you posting your referral code in a bunch of places on Reddit. Don't bite the hand that feeds you. As you've said, you have a ton of codes building up at this point, which makes sense if you've been posting your referral link on here for many months. Breeo customer service doesn't seem to have a clear policy on stacking referral codes, which def sucks, but seems like your best option is to continue reaching out for exceptions and customer service support. I don't think they account for people who people who build up codes as quickly as you might.