If this begs more info...photos...clarification...whatever, I've found Trainz to be very responsive to and appreciate of questions.
A few months ago they posted a 3rd Rail engine that was a mismatch of loco and tender. I traded several emails with their representative who was very nice about it all. Finally, they confirmed that an earlier engine/tender sold from the same collection had the matching 'mismatched' engine/loco. There was no possible way that either set would be operational as-built, unless they had been modified. The earlier buyer had made no comment before or after the sale. They confided that the whole collection had been boxed by the estate heirs who were not as involved in the hobby as the deceased.
Nonetheless they indicated they were going to contact that buyer, see if a swap of tenders could be made. In the meantime, they pulled the mismatched auction.
Long story shortened, the earlier buyer agreed, the tenders were swapped, Trainz made a properly priced sale of the second set. (I chose to not bid, already having the same set, different engine number.)
Bottom line...they communicate...they listen...they'll take steps to make it right, if possible. I have NO hesitation in communicating with or buying from Trainz.
In fact, I think for an item like this highly desirable/collectable 773 set, it behooves us all to bring a possible mismatch to the seller's attention. If it's sold as posted to someone lacking the concern for and/or knowledge of the potential mismatch, someday it'll probably hit the market again and the same error will be even more embedded by time. If, as in my example, this is a recent error, a responsive seller like Trainz might be able to get everything (pun intended!) 'back on track' sooner, rather than later! Not everything need be 'It is what it is!'.
FWIW....
KD