Not saying that rep system is perfect, but it works pretty well at giving you an idea of what to expect when playing "a player". The biggest draw back is that the players that win a lot and are in 2500-3000 ELO will usually have a Neutral (maybe good) feedback because, well, lets face it, people hate losing and one way to get back at the winner is to Bad Rep him - so that's what they do. But these people usually are Neutral or below themselves.
The scenario you put forth however is highly unlikely. Very Good feedback is VERY hard to maintain at 2000+ ELO. What you are saying is that you win Fair and Square and they are Bad Repping you. And that these guys use ITST mod. I find it extremely hard to believe. What likely happens is that your gameplay/style is the cause of bad repping. Considering you not naming any names and concealing your own identity - it is hard to take this posts seriously.
If you want to do this in private - please contact me, we will discuss who are these Very Good rep people who bad rep you, we do not tolerate such behavior at ITST and I would be glad to address it.
ITST General Manager