I emailed the Mojang team on 6 April, after IOS update, about a purchase of coins that very same day but showing as 0, plus then my son finding all of his worlds purchased thus far have disappeared too. I am following this so that I can check all money spend is returned by Mojang once the bug fixed! I am just glad I have kept all receipts Apple have emailed me as evidence!
Hi Helen
I have just forwarded my email to you after I had reported issue via email on 6 April. My son's coins are still showing zero. To be honest, I am considering contacting Apple directly to claim refund as dealing with an upset child for this long is simply not worth waiting!
Silvija