Infinity Plus Two has repeatedly been found to sell loot boxes missing the best items or containing them at significantly lower than advertised odds. They always deny this at first, deliberately spread misinformation and ultimately refuse to communicate further once enough proof has been presented. Avoid spending money on the kingdom pass, you may receive some entirely other troops than announced, their support will just ignore you and close your compensation request.
For the most recent case of faulty loot boxes and how they were handled, see this thread and this summary.