Speed down to 0.25 Mbps from 3Mbps

[#1]

Over the past two weeks I noticed a gradual reduction in speed for my PlusNet Broadband connection from 3Mbps (0.5 mile from BT exchange Lee on the Solent) down to 0.25Mbps (max).  I have checked all of my equipment in accordance with PlusNet guidance and run the BT W test using two routers and the best I get is a download speed of 0.19Mbps.  The BT W diagnostics check revealed a new cap on my broadband speed of 0.25Mbps.  My router is a Thompson: Noise margin 22.0/9.5; speed 440/283 kbps; attenuation 32.5/51.0 db.  I have had to cancel my subscription with Netflix. as I can no longer stream content - not that I used it that much.  Even the BBC iplayer will not work even on very small screens.  The BBC home page takes over 17 seconds to load.  I have had PlusNet for six years and this is my first problem.  Finally, I have made tentative enquiries with other providers and they said that my speed is too slow even for their basic deals.  I am at a loss. What could have happened that has led (presumably) to  BT capping my service? 

[#2]

The first thing is to raise a fault http://faults.plus.net
What has happened is that your line has been banded due to instability
Note that with a 51dB attenuation your line length to the exchange is about 3.7km to the exchange so one thing to do is to try the test socket - this explains http://community.plus.net/forum/index.php/topic,96155.0.html and see if it changes

[#3]

Hi there,
I've just had a look at your fault ticket (72300683) and can see that you resolved this yesterday with our faults team. I'll leave it up to you as to if you wanted to comment further.
Just let us know if you need any further help or advice.
Adam