We stumbled across several inconsistencies in out contacts where a support request did not help us at all (but we were referred to this very forum here).
We e.g. have two contacts where there is only one email visible in the frontend but where the API returns two. In the API for both the primary email address is the one not visible in the frontend. On both contacts, it is not possible to add new email addresses through the frontend (I guess there is no API action to do that) and so we cannot make the data consistent. Only adding a new email address would allow us to make the new address primary so we could maybe trigger updating the (probably) broken data underneath.
As mentioned before the customer support does not even understand what I am talking about. Is there another way so that we can trigger a fixing of inconsistencies like this?
These are only the one issues we stumbled across by accident so I assume we might find more in the future so it would be very important for us to have a well-defined channel to handle issues like this in a professional way.