MCPE purchases are locked every time it updates and Mojang hasn't done anything about it, so does anyone have a solution?

Every time I update MCPE on my iPad I lose everything I have purchased in the app, mashup packs, mine coins etc. Just befor the 1.2.14 update I bought some mashup packs again only to lose them the next time MCPE updated. I can't find a way of fixing it. I've lost a lot of money on this and I'm sick of it now! I love minecraft, so have put this down to a bug (that seriously needs fixing)! For the last five updates at least Mojang has done nothing to fix this, so I'm asking if anyone else has found a way to solve this? Before I give up!