Due to data privacy laws in various countries Adopt Me is available, in addition to our own data retention policies, we here at Uplift Games can only hang on to player data for a certain period. You can view our Privacy Policy here, particularly Data Storage.
Player data includes things such as trade history. As such, if a trade has been removed from your trading history, it is likely due to these laws.
Once a trade has disappeared from your trading license, we also no longer have access to these trading records, and so cannot assist in any trade-related issues beyond that point.