Ultra Tile have a forum Member Support Account: View Profile: Ultra Tile - Tiling Forum | tilersforums.com - though you will probably need to call them etc.
Take some pictures of the adhesive on the back of the tile for us, and also the SLC that you can see when you've lifted the tile. That might give us a clue.
Take some pictures of the adhesive on the back of the tile for us, and also the SLC that you can see when you've lifted the tile. That might give us a clue.