Internal investigation was not helpful - Senior Product Designer Zalando Employee Review

Not long time ago, I posted a review for Zalando, describing the mobbing I was facing from my managers who had secretly changed my performance review record and got me fired. Zalando replied with a kind message asking me to report the issue to their internal whistleblower tool. Which I did. I wrote thousands of words with screenshots as evidences. After a couple of days, they replied to my report claiming that the described behavior is not agains their “standard”, without disclosing what types of investigation they did. TBH, I am not surprised, after all I have left Zalando already, who will take the risk and take the case seriously? It is an “internal” tool after all.