I have had nothing but superb customer service with Expedia. In fact, I just got a refund on a half-used Thai Airways ticket processed quickly and without any hassle. A similar refund I've been trying to get through Easy Sabre is dragging on forever...

As for hotel rates, all the online services post multiple rates. Unless the rate specifies government employees only, AARP, etc., just pick the lowest rate for the room you want.

If the Expedia confirmation shows that your flight was leaving from MIA and it was really leaving from PBI, that's a serious problem! I've never heard of that happening before, but it would certainly demand full compensation from Expedia and I would expect they would comply.