I'm in Christchurch and have Choice Naked Red Broadband and have a Cisco ATA box off it. On Wednesday we started to get a lot of drop outs so called 0800 438 448 and found the CSR both helpful and knowledgeable. After about an hour eliminating all possibilities it was decided that the fault must be on the line.

Around 10 the following morning the tech from Chorus was knocking on the door. The culprit apparently was an old Telecom diagnostic box which was interfering with the broadband data. Disconnected and normal service resumed! 

Pretty awesome service from Vodafone and Chorus I reckon...