The company that owns Suncoast (and Sam Goody, etc...) was recently bought out by another company, which means Suncoast's vendor agreement with ADV has been severed. They are working towards a new agreement, but as of now it is very difficult to get ADV anime and ADV distributied anime through Suncoast. There are some titles that were due in the stores in Feb. that Suncoast has yet to receive do to this issue.
You might also have noticed that they used to carry manga for a brief time. The dissappearance of manga was also a consequence of the buy-out.
Hopefully they will come to an agreement soon, but until then, you might want to get your ADV and ADV distributed titles from Fry's electronics, or online. With the Suncoast member card it was much cheaper to get anime from them, but with the delays as of late, that's not really an option.