The many topics here noting Orcon's lack of customer service makes me realise that switching to another provider might be the best answer, but hopefully you guys can help as I think this might actually be an easy fix.

A while back our cabinet was upgraded to VDSL.  Information from anyone about this was vague at best.  I won't repeat the whole thing for the sake of brevity, but after a lot of hassles a Chorus technician turned up and it turned out our modem (Linksys WAG200G) was no longer compatible.  The technician said "Buy a new modem, and you'll need to get new settings for it from your ISP."

We bought a Linksys WAG160N and while it works the speed is a third of what we got before the cabinet upgrade (200Kb/s is about the max we get now).  Despite repeated attempts to get through to Orcon we simply cannot get an answer out of them about any new settings for the modem.

I've tried fiddling with a few different settings but I'm mostly fumbling around with no real idea.  I wouldn't have a clue and Orcon are at this point non-existent in the process.  If anyone has any ideas I'd be very grateful.