Going to a manager in contract is never a good idea even if you show diplomacy because the manager can do nothing but hear your complaint, monitor you, and report you as someone that could be a potential threat. Even if you are positive and especially if you provide a solid solution with respect; You will be watched and the documentation process to get you out will have just begun. If you follow up with your manager, they will tell you it's being taken care of and technically they handle it by pushing the person who submitted the complaint out. This did not happen to me personally, but I have watched it occur at least three or four times with others in the past. I did not think they were offensive or insubordinate. They were performers with very good reputations.
The managers job in contract, is to see that the herd is going wherever they're or led to and to report those that think independently. As a manager, you get away with having a little bit more independent thought on contract, however you are always outside of the respected circle of leadership that works directly for a client on a project. The pecking order is a solid hierararcial structure where the contract representative is on the absolute lowest level. It's sad and a bit ridiculous.
I have a gut feel that the previous post is either in HR or is a contract manager that has become very comfortable with being an authority albeit in a lower position in the grand scheme of management versus the client, but still above the sales rep level. I guess as long as you're not the lowest man on the totem pol, it suits them.