Small Claims Court is a small informal court, and is a low cost way to sue someone for a small claim. You were flying from Baltimore, so I will provide a link which explains the system in Maryland, but it is available in almost every jurisdiction.
Wait a little bit longer before you file.. but not too long. Delta is particularly bad at customer service and has the arrogance of a monopoly which has walked away from it's obligations before through bankruptcy. They are very poor at responding to consumers, whether you are a frequent flyer or not. Your best bet is to stop flying with them, particularly when travelling internationally. Their international product is almost never as good as the competitors.
Anyway, here is the link which explains the Small Claims court process.
http://www.peoples-law.org/misc/small-claims/howto.htm