Having worked for Amazon recently I would say the following:
A) they are an ENORMOUS company and just about every interaction they have between individuals (especially from different locations) seems to be carried out in a digital manner. COVID aside, they carry the corporate defensive strategy to the absolute limits so it’s hard to point a finger at part of their empire and take a pot shot at it.
B) Just because their “corporation “ is unable to tell you anything above and beyond what your account activity shows to any of their “customer handlers” doesn’t mean they are unaware of irregularities with your orders, only that they’re unprepared to discuss them with you (after all, that would be admitting culpability on the behalf of their company which NEVER happens..anyone who did so would immediately be guilty of bringing the company into disrepute and looking for a new job the same day with the epithet of Gross Misconduct on their CV)
C) if an individual within the supply/distribution chain has been misappropriating items, rest assured, they are aware and have a procedure for tackling this scenario although it’s something they would never ever discuss with any of their customers.
D) stick to the advice you’ve been given by others on here and deal with them on their normal channels just don’t expect an intimate interaction and live with the fact that they will resolve your order to the best of their ability. Live is too short to waste time venting your spleen (even if it does provide an emotional crutch for disappointment) so move on and devote the rest of your day to something which lifts yours or others spirits