Mention their name. It's Ernst & Young.

I think you are over-estimating what an auditor is expected to do. Auditor's, to me, seem to be there to make sure you're compliant with the law or regulation that they are auditing for. In these audits, the company gathers and presents all of the data that the auditors will see.

The auditors will do interviews with people, but the company also (somewhat) picks who will get interviewed.

Remember that auditors are paid for by the company they are auditing. They are motivated to do the minimum required to pass the given regulation. They aren't there for true oversight, they are there to make sure all the checkboxes are checked.

Yes, but the understanding is that the auditor gives approval of your "books" and companies should not be able to function for years while doing fraudulent things. This is why there is audit in the first place. It is mandatory and they should be held accountable for it.

EY did catch them eventually. I'm guessing the courts will be doing a review of the audits that EY did over the years. It's likely a matter of how deceptive Wirecard was to their auditors.

No, EY just refused to rubber-stamp their books again after KPMG had already raised the red flag about Wirefraud.

In theory they could provide a qualified opinion (which basically says: this company is screwed) or withdraw from the audit (which will signal the same thing).