Something FISHY at DL
 

I was ticketed on DL, ISP-FLL-ISP yesterday for an amazing fare of 103+. The fare was probably to match WN at ISP. Anyway, I figured I could book it now and cancell it if I couldn't arrange for the days off. I looked back on DL.com to find the exact departure times and the ticket was gone. After hours on the phone with DL, the supervisor told me that all the flights from FLL-ATL-ISP were oversold and all the fare classes were zeroed out. She told me something was changing on these routes and she was unable to book anybody from FLL-ISP at the moment for my dates. She told me my flight was now showing an oversales of 80 seats - this on an MD-80 which was showing an empty seatmap and all 9s in the inventory just 30 minutes prior.
I asked her how to solve my problem of finding a return (the outbound was still going to be honored). She told me that the itinerary that I had was not ticketed but only a reservation that "must have been cancelled". I was outraged because you cannot reserve the seats, you must buy them at DL.com. She was giving me some line of garbage and I finally asked for a coordinator. Her boss told me that he understood what had happened but, even he couldn't book the fare for that flight or any fare from FLL-ISP on December 4th.
He is the kicker, there is inventory if you search FLL-ATL and ATL-ISP seperately. Booking the trip that way comes out to be almost $500 though.
WHAT IS HAPPENING?
SR

They may have pulled the fare. In looking at ISP-FLL departing Dec 1 (just a guess) these are the fares offered.

It may have been a sale of some sort, and then pulled for whatever reason.

If the flights are all showing "0" as inventory the flight is likely to be forecast to be cancelled.
if you are able to book the segments point to point the problem is with the Inventory Management System.
Basicly Delta is not interested in allowing you to occupy a seat on the FLL to ATL, or the ATL to ISP flights for the fare you specify, Delta would rather sell the seats to someone else that is traveling from XXX through Atlanta to FLL. and XXX through Atlanta to ISP that has a higher revenue potential

So is there anything I can do? They won't let me return at all to ISP on the 4th of December! My original itinerary is still missing.
SR

I don't quite understand what the problem is. Delta isn't interested in selling tickets from FLL to ISP on December 4th, and you don't have the problem of holding a ticket for a nonexistent flight or anything like that. You haven't bought a ticket, right? The solution seems pretty simple -- fly Southwest or some other airline. It's not "fishy", it's just Delta changing fares and schedules a thousand times a day like any other airline.