Issue with PetShop not loading

We purchased the Pet Shop for Minecraft over a week ago and have tried everything but it will not load.  We go in and it looks like it is going to load but then after a few seconds it goes blank and takes us out of Minecraft.  Our iOS is up to date and so is Minecraft.  Very disappointed.  If someone can please tell us how to fix this or provide us how to get our money back that would be greatly appreciated.