I have been a Snap customer for years and I never experience any issue with my broadband until I moved to Auckland. (Well, it might not be their problem)

I am renting in Lynfield, Auckland since October last year. With no hesitation, I called Snap and subscribe to their naked ADSL plan (ADSL & Snap Phone Plus) and bought a Fritz box 7490 from Snap.

Since I got connected in Oct/Nov last year, for the first few weeks, the modem would lose sync (No Info LED, Power/DSL LED blinking) for a couple of minutes then it synced again. However, the speed would drop to around 1M after re-sync. I tried power cycle the modem, unplug the cable... I cannot get the speed back up. I used my previous TP-Link modem and it also exhibited the same issue. At random time, normally a day later, the speed would return to around (6M-8M) then at random time, it would lose sync and drop again.

A Chorus technician came to my rental property and cut off all the wiring so only one phone jack is usable. We changed the modem cable, change the wire pairs all the way from exchange to the phone jack, change the port in the exchange but now for the past couple of months, the modem loses sync more than 10 times a day, the worse time is in the afternoon, it loses sync every 2-4 minutes. After the sync is re-established, the speed varied (like 700k, 2.xM, 4.xM, 5.xM, 6.xM) each time.

On Monday, a Chorus technician came and after we swapped the modem, we could not get sync at all. He rang Chorus and asked for port reset and I heard the guy said reset the port will not get the sync up but he did a reset anyway. So this Chorus technician checked every single point from the phone jack to the cabinet and could not get the sync (voltage test, isolation test...). When he went to the exchange and connected the tester, the sync came back. In the afternoon from 2pm ish to 4pm ish, there were heaps of lost sync, every 1-2 minutes, then it became more stable after 5pm but still had a few lost syncs.

Last night, Snap remotely accessed the Fritzbox to change the stability settings (they didn’t tell me what they have changed) but since then each time the modem loses the sync, it never re-connect again. I did a factory reset this morning and now, each time it loses sync, it will come back in 1-2 minutes.

I already made a lot of calls to Snap and they have run a lot of tests. Three Chorus technicians came to have a look but the issue is still persist.

What can it be? Anyone?

Some information:
Exchange is 2.xkm away. Cabinet is less than 1km away. It is not "cabinetisationed" according to Chorus Tech.
Line attenuation: roughly 36dB.