Allow me to give some background information, so you may understand my situation better.
We have been prone to sending emails to unintended recipients, many of which contained confidential data. Email is the only medium of communication. We do not have a CRM. Customer Service Associates (CSA) can be untrained, or the intended recipients change frequently. As you can imagine, this is kind of an ad-hoc setup.
What I would like to get your suggestions on are, how do we make sure that any file that goes out of my email box is password protected? The second and most important question is, is there anyway that I can share documents in a Dropbox kind of way, where the CSA can only add the link to the document in the email, and later on, if we find that that the person was not supposed to receive the email, we can just delete the file from the Dropbox and no harm done.