Cross Platforming Market Place

At one point when I only owned Pocket Edition for my kindle, I had purchased a lot of skins and textures. Now I have both Windows 10 Edition and Xbox one edition as well as the pocket edition, and the FAQ's said that any purchases made should transfer across platforms as long as it's on the same account. However, I only have access to any of my skin packs or texture packs on my kindle at this time. I wanted to use a specific skin and texture across each with some friends but it won't let me do so because of this error.