what item is it?
you can't make in app purchases through the hacked version. you have to download the original from the app store. from there, purchase whatever lootbox you want and leave it in your inbox unopened. uninstall the original, install modded, open lootbox in the modded version. it'll dupe it to 10,000 lootboxes lol.
tbh, i don't really recommend it. you'll (probably) end up with thousands of leftover lootboxes in your inbox once you get what you're looking for. i did this and have so many leftover boxes and i had no desire to open them all so i just made a new account lol.
i'm afraid having that many lootboxes will flag kefir. even though i've heard they haven't actually banned any ldoe accounts from # of lootboxes / inbox items / too many skill points, what if they implement something in the future??