Complaint Review: Expedia

My wife and I booked a trip to Mexico with two other couples and each of us paid the double-occupancy rate advertised by Expedia; i.e. three couples paid for three rooms.
The itinerary only stated a single room, so we called to explain that we are three separate couples so need three rooms. The Expedia Agent confirmed that we would have our own rooms, but when we arrived in Mexico the hotel had us all booked together. I ended up paying for an extra room (even though I already paid Expedia), and figured that this obvious error would easily be fixed when we returned. NOPE!

The fact that each couple paid the posted double-occupany rate (i.e.
we paid for three rooms), according to Expedia, does not suggest that three rooms would be provided. Their evidence? The incorrect itinerary...
The recording of the Expedia Agent discussing our concern by phone, and his assurance that we each had our own rooms is selectively ignored by Expedia.

A 4th couple booked directly with the tour operator (not Expedia), paid $50 less each, and received a room. Double-occupancy means two; but not according to Expedia.