I won't beat the dead horse on who's ultimately responsible. my bigger takeaway was the op's perceived lack of caring about the issue from the dealership side. granted we're only hearing one side of the conversation with the sales manager and there's always 3 sides(his/theirs and somewhere the truth) but here was a missed opportunity as a retail manager to help make a customer happy which at some point could lead to a trade in of the mojo toward a max.
my gut would be this experience does sour the relationship a little. maybe not to the point that the op seeks another mechanic but when trade time comes they do have a longer uphill battle than if they would have helped the op.

as a sales manager, show some empathy, offer to pass the feedback on to the shop manager and perhaps a free towel or discount on something.