I would say the first economics theory that could relate to the letter would be the Laissez-fare economic theory. In this case, law enforcement did not get involved with incident until long after the breach was discovered. The government did not intervene to protect the user’s privacy until after the incident happened. The Rational choice could also relate to the incident described in the letter. The company clearly didn’t choose a partner that invested enough into cybersecurity and suffered for it.
As for the social sciences theories (which I am assuming is supposed to be the Sociological Paradigms mentioned in chapter 7-8, since I couldn’t otherwise find a reference to the term in our notes.), ones that relate to the letter would be Conflict Theory and Symbolic Interactionism. Symbolic Interactionism to me relates the most, since the users interaction with website exposed them to getting their information stolen.