We have purchased a number of paid worlds on my sons Minecraft game and they never download.  I can download them on other devices logged into the same account.  I have logged his account out on the iPad and logged it back in but they will not download.  He doesn't want me to delete the whole app as he has put a lot of hours into building his own worlds, which don't seem to transfer to the other devices with his account details. He also constantly gets an error message saying that there is an incomplete Minecoin purchase and to check connection to the App Store, but it is all logged in.  Your assistance to fix these problems would be greatly appreciated.  Please let me know if you require his user login details.  Thank you.