Got home from a week away yesterday and the internet has been dropping out every 5 to 15 minutes since then. 

2degrees support have been friendly but not very helpful. The rep I talked to this morning said they needed to do an "extended line test" to diagnose the problem, which would take 12 hours. Seems like overkill when you can see the problem happening 5-10 times an hour, but I figured we best follow procedure...
...called back in the night and was told the test still had 40 mins to go and they couldn't get any results before it was completed... so I waited...
called back just now and the CS rep told me the test "didn't go through" because "the modem has only been connected since ten minutes ago". Because it's disconnecting all the time. Which I told them was the problem in the first place! 

Got a Chorus tech coming by "in the next 24-48 hours", I'm paranoid at this point that they'll also just shrug their shoulders and tell me they don't know what the problem is. So I'd like to get some ideas what could be wrong from the people here.  Here's the typical event logs the router's been showing (Fritz!Box 7390):



Here's the rest of the DSL stats:




So the SNR has gone to crap, last time I took note of it, it was 13/19 receive/send, now it's only 9dB both ways. 

Is it worth fiddling with the "line settings" tab in FritzBox? It's been set on "Max Performance" since forever.