Very Low NBN Speeds

[#1]

Was switched over from Optus Cable to Optus NBN on 4th February and have had terrible line speeds since then (often below 5Mbps and sometimes less than 1 Mbps), even thogh I am on a plan which promised much higher speeds. I had a good service on Optus cable, now it is worse than the cheap dial-upo I had in the 1990s. I have spoken to Optus technical support, and it was a little faster for 24 hours afterwards, then it dropped back to where it started. Can anyone explain why? 

[#2]

Optus (and the NBN) are legally required to hit close to promised / paid for speeds. 

First thing is to ask Optus to run a line speed test from their end to see the speeds possible. If they say its running a lot under what you are paying for then they need to get NBNCo to fix it.

Minimum legal NBN speed is 12 Mbps. But if you're on a 50Mbps plan for example then than needs to be provided (legally). 

I take it you are on FTTN 

Peter Gillespie