Your first mistake was assuming there was a code of honor among captains. Your second mistake was thinking if there was one, that captains would actually follow it.
The reality is this stuff happens all the time. Teams play random order and stack and some don't and play straight up. Complaining to the LC will fall on deaf ears. No rules were broken. No code of honor real or imagined was violated. If you want to improve your rating like you suggest, you should play up. That is probably the fastest way to raise your rating to 3.5 assuming your are at least somewhat competitive.