First I'll say that this has never happened to me before. On any international or complicated itinerary, I ALWAYS check mileage accrual rules in advance.

In this case, I booked a flight from YUL-DEN using my corporate booking agent all on AC (I actually made sure not to get the YYZ-DEN flight on SkyWest since it's so horrible) in economy. It was $400 for the one way, so naturally I assumed it was a standard economy class ticket. Didn't even think to check mileage on a "domestic" ticket like this.

Needless to say I was shocked to receive 25% credit on these flights because it was apparently in S-class? What?? Evidently S, T, L, A, and K classes earn 25%, but I thought those were Tango type fares bought on AC or bulk tickets, or super discounted. $400 for this routing is far from discount.

Any recourse here? And no, our travel agent doesn't have a specific relationship with AC at all where tickets are always sold into discount classes.