I've had a look over the fault ticket on your account and firstly want to apologise for the length of time that the fault has been ongoing.
I can see that the fault was raised to our supplier and after the initial tests that we completed it was advised that the problem was due to a large number of uncorrected blocks on the line most likely caused by your internal setup or poor line quality.
Its clear that the problem is due to the faceplate fitted by BT with the built in filter and I can see that we are arranging an appointment to have this rectified for you.
I appreciate the frustrating nature of having an ongoing fault, and am sorry that you feel you have received poor service during the fault investigation - the requests that were made of you to test certain things at your end were required to progress the fault. It is unfortunate, due to the nature of ADSL technology, that some faults can be harder to diagnose than others. This obviously leads to longer resolution times for which I apologise.
Hopefully BT will make the necessary repairs and your connection will return to normal in the near future.