So for multiple times this week I have slow speeds down to 2.55Mbps but at least its not a total loss this time. On hold time is 50 mins and pressing 1 to get a call back doesn't work, welcome to 2020.
I have checked your NBN-FTTN 12/1 service on our systems and all tests are passing.
A 12/1 plan with heavy household usage can appear slow at times because the 1meg upload speed becomes a bottleneck and sheared downloading skews speed tests.
For heavy usages, a 50/20 plan will provide much more reliable speeds to heavy usage situations.
Here is a doc to help TS speed issues.