It has been clarified--to some extents--how to cite e-mail communications from "individuals". For instance, in APA style:
https://www.apastyle.org/learn/faqs/cite-individual-email?apaSessionKey=JbXO7F2y7V0Xj6ZHTmByrOII
My question is concerning "companies" or "organizations", especially when you prefer not to mention people's names (or even the name of the organization/company). This may happen when they provide you important but wrong/inaccurate information unintendedly. On the one hand, as a researcher you do not want to mention their names to ruin their reputation, and on the other hand, you want to reflect such ignorance in your publication to show a gap in the existing culture.