Comixology app before Amazon was excellent, but Amazon has destroyed it. The UI is not in the least user friendly, several useful features are gone, but what's worse is that, even after syncing twenty times I am missing over 300 issues. They've just vanished like I never bought them. Fortunately, I've kept a record of most of my purchases, so I will present Amazon with a bill for what they owe me. It's absolutely disgusting to be treated like this by a company as hugr and wealthy as Amazon.