Disconnected at regular intervals

[#1]

I'm incessantly losing connection to the internet for a few mins, but at regular intervals. They're spaced at 30 minutes, 60 minutes and 120 minutes.

Does anyone have a clue what's going on, and/or what I can do to stop it? Every time I line up to battle with my gaming teammates, I get disconnected. At this rate I'm going to get shot for desertion. 

[#2]

Looks like it's been stable for the past couple of days.

Our tests have found a external fault which we've raised to our suppliers.

We'll update you as soon as we know more.

[#3]

It's not stable. It's just MORE stable. I still get dropped repeatedly.

I also got downgraded to ADSL somehow. That's supposedly being fixed today and my line is being returned to 80/20. Supposedly. I read on my ticket that the date is set for 30/08 rather than 23/08, but the notice I've had says it's today and since nobody has officially told me any different, I'm HOLDING Plusnet to it.

To say I'm annoyed about the handling of my service, the lack of communication and the total absence of anyone at Plusnet who gives a *&^% would be to understate things. I'm livid.