In reply to a post by RobertoS:

Very unusual for it not to connect on ADSL2, which is often the best setting on dodgy lines.

G.DMT (ADSL) is more stable than ADSL2+ because ADSL2+ uses twice the frequency range, the same as G.DMT plus the same number above those. Those higher frequencies have two problems.

First, they attenuate more, which is why on long lines they become useless and there is no speed gain, and second they are more prone to interference. Noise.

As a general rule the higher the speed the more errors there will be, on G.DMT or ADSL2+, and more noise almost by definition means more errors.

High error rates can trigger a disconnection and reconnection.

Brickwall time I think.

They don't seem to be able to connect the fact that I stopped water getting into the outside junction box a week Saturday and seem to think that it was their actions on a week Sunday that helped to resolve the problems and now don't want to drop my SNR margin back to 6dB. 6dB is what the lines been running at for years without problems but that seems to be largely irrelevant.

Think I'm going to give up before I go mad.

In reply to a post by IAmATeaf:

They don't seem to be able to connect the fact that I stopped water getting into the outside junction box a week Saturday and seem to think that it was their actions on a week Sunday that helped to resolve the problems and now don't want to drop my SNR margin back to 6dB. 6dB is what the lines been running at for years without problems but that seems to be largely irrelevant.

Think I'm going to give up before I go mad.

This is, unfortunately, a reasonable approach for them to take - and an example of what happens when too many people have hands on. Quite naturally they will want theirs to be the solution, and I don't suppose they'd bother to look at the history of your line -even if they had it to hand.

Good luck in your fight

I've given up to be honest, 12dB is what the line will stay on is what I've had back. Doesn't matter about past history, after the fault the line has been regraded by them to have a 12dB margin.

If it wasn't a business line I'd have voted with my feet a long time ago.