Almost certainly not. I've had some truly dreadful experiences with Expedia (e.g. shown up at hotel on prepaid reservation and been turned away... twice!).

Did Expedia mail you any receipts (or actual tickets) yet? If you get paper tickets, then you should be in pretty good shape (since I'm presuming you booked full Y, they are basically cash). For etickets, I'm guessing that Expedia outsources to a local agent. Chances are, communicating with this local agent would get you much further than calling Expedia. I hope your flights go smoothly.