Appalling service (Broadband internet connection unreliable since February 2013)

[#1]

I have been acting for a friend in reporting a fault with their Plusnet broadband connection since February 2013!
(Plusnet personnel see ticket #66122717)
The problem (repeated loss of connection) remains, despite at least 4 visit by BT with no fault found on customers pemises each time.
To whom within Plusnet can I make an official complaint and can anyone advise which body/ombudsman, etc (ie external to Plusnet) that this matter may be referred?

[#2]

Hi edavies,
I'm really, really sorry for the ongoing problems that you've been experiencing. I've just had a word with my colleague Simon who has been dealing with this issue for you. Simon is going to give you a call now and he will also deal with your complaint from the Plusnet side of things.
In terms of complaining externally, I would advise allowing us to deal with your complaint in the first instance to see what we can do for you and how we can help you further. I am sorry for how long this has been ongoing for, it really is unacceptable.
Simon will be in touch shortly.

[#3]

I'm having the same experience with plusnet customer service: my latest ticket has been open for over 3 months and the broadband service is still unreliable, certainly not cheap, and about half the time slow or suffering single or multiple disconnections.
The fault reporting system works fine until they laboriously discover that it is not the customer's equipment that is the problem. I have had several engineer visits, all finding that my equipment and my line to the exchange are fine. The suspected culprit is now REIN - noise interference which could be anywhere along the several kilometre line from here to the exchange. A major delay in this bureaucratic process is that they do not test the line when there is a problem and so we go round the houses for months on end trying this and trying that instead of focussing on the fault when it happens.
Plusnet is eager to find fault on the customer side but very slow and lax when it comes to investigating problems on their side. They are also secretive and evasive (or is that clueless?) when it comes to technical facts. They do keep apologising though, of course, this doesn't fix the problem.

[#4]

Richard,
Welcome to the forums.
I suggest that there is a very different perspective to your issues - REIN is extremely difficult to locate, is predominantly caused by consumer equipment (yours or a neighbour's) which even if located, no one has the real power to eliminate.  REIN can arise from: faulty central heating boilers / thermostats, switch mode power supplies, fridges, plasma TVs, Freeview set top boxes, CCTV systems, weather systems (even miles away) and in my case passing electric trains.
One thing you could do to help profile the problem is to install routerstats and run it 24x7 to monitor your SNRM.  If you want to follow this course of action, there is a lot of help available to you here.
Kevin