Can anyone recommend a data cabling technician on the North Shore in Auckland?

When I first did my set up some years back I had no hassles at all.
But now after events a week or so ago it seems as if the whole setup is jinxed.

At first I thought my master filter was faulty so I bought a replacement but I still cannot get things right.
I can get broadband with no problem at all, but as soon as I try to connect up the master filter and/or the phones everything goes pear shaped: cannot get ADSL connection and the phones ring until I unplug them.

So I think I need to get a cabling techie, or perhaps an exorcist to get this mess sorted.