> we immediately banned Kogan's app from our platform, and demanded that Kogan and Cambridge Analytica formally certify that they had deleted all improperly acquired data. They provided these certifications.
To generalize the issue, if you were in charge of APIs at some company A and some company B (not necessarily located in your jurisdiction and not necessarily subject to the same legislative framework as you) told you they used to have the data, but deleted it since then, what additional measures would you recommend company A pursue?