I got that response yesterday and called back 30 minutes late and was able to make a reservation. I would try back ASAP. Try calling early in the day if possible Right now reservations are getting very hard to get, especially in EPCOT because of some restaurant rehabs. For the date I wanted in early October I had one option between 5pm and 8pm. Get a reservation, even if it is not exactly what you want then call back for cancellations. It's not like making reservations at any other place you are used to. Some people make them 180 days ahead.
Hope this helps