Some of my sons purchased packs on minecraft have a problem. He can't create a world with the packs. A downloading bar and blue box With an exclamation mark is shown on the icon for the world/template he purchased. The icon usually says 'owned' in yellow. When you click on the icon the grey box where the price would be is greyed out completely - normally it would say 'create this'. Please can you help - as said, these are paid for worlds, recently paid for. He has space on his device and he has played on these before so they had downloaded before. Please can you help fix.