That sucks. I'd expect Telstra to be on the ball for infrastructure. I expect this from TPG though, since they're leasing a lot of their lines from others (ie. Telstra ) and are cheaper because they skimp on backup and support. Which is fine 99% of the time, this unfortunately is the 1% though.
I was looking to see if it was worth switching ISPs, but Tesltra is too expensive, Optus tells me I can't get shit with them, iinet doesn't let you get a plan without bundling with phone crap that bloats the price beyond usefulness and confuses me. Most other ISPs just seem like crap to me and not worth trying.
The last time I checked iiNet the phone bundle just reduced the price, so that's pretty lame if you can't get any plans from them without it now. And yeah Telstra has the infrastructure, but they're lazy and don't give a shit.
When the problem started for me I was doing traceroutes and found that all of my connections to the US were being routed through SEA and Europe instead of going through the Southern Cross cable as usual. It meant I could do simple web browsing without too much difficulty (it'd just take slightly longer to load pages) but downloads were a lot slower and streaming impossible. Is your traffic being routed through Europe or is it still going through the Southern Cross? It might explain why your situation is currently shittier than mine.
I read about it but can't remember, and haven't checked it myself, but my experience sounds similar to yours. I can load pages mostly fine, although some take several seconds longer. I haven't been able to download a single file all day though, not even a 7mb MP3 file. Downloads go at literally dialup speeds, and just fizzle out after a few hundred KB's. I can't go a month without being able to download any files. It's 2016.
I was mistaken on iinet, I can do it without any phone stuff, but without the phone stuff, the prices are hugely beyond ridiculous. With the phone plans, the price is only slightly beyond ridiculous.