Glad to hear the problem is sorted.
I ran across a warning for this issue when doing research on the topic before CAT 5 wiring my house in '96. As for the IT guys, they rarely install or make cables, they typically use pre-made cables for the short runs and hire installers for the stuff in the walls, etc. Professional network cable installers have a fancy (and expensive, about 300 BP) gadget that catches crossed pairs by sending tests signals and evaluating the result, so the IT guys have likely never seen this issue.
