It's difficult to comment without the full facts but on the face of it if the other chap was going the wrong way downwind it sounds like the problem was all his.
Did you speak to ATC afterwards? Ringing up in a reasonable tone (i.e. don't lose your rag however you feel justified) should be received in the same way and you may learn of other factors that were not apparrent at the time. But do say if you were unhappy with the situation. At the very least I would expect the other pilot to be 'spoken to'.
As for reporting, if you feel at any time that you were in danger of collision then it is available to you to file an Airprox report. It is then investigated by the authorities.