Broadband issues, Been going on for months now...

Question

Basically i joined BT back in January 2010, First month i had a few dropping connections put that down to basic things such as the line stablizing, February it didnt get any better so rang BT regarding it, They sent an Engineer, After fault finding he had no clue as to the fault so i monitored it myself over the next few days and worked out an emerging pattern, My Flat is situated not 30ft from the West Coast Mainline with the high speed Electric trains going past, Everytime a Train passes the interference thrown off from the line was enough to knock out the connection to the Server.  Called BT again in March they sent an engineer who capped my line at 3.4mb/s 60% of what the maximum speed was to give me some stability that fixed the issue for a time until the next month when the server reset the speed back to the original value (something to do with it testing what the max possible speed was) Trouble was the test was done under conditions where the trains were not passing at that moment, Yet more dropping connection issues, they sent a 3rd Engineer out, he fitted a ADSL Faceplate to my Socket and said he figured it was the electrical interference messing with the microfilter, he turned down the INR Values back to 60% after i told him what the previous Engineer had done, it was fixed for another month...
April there was a 4th Engineer whom fitted a Small filter box above the socket, turned down the INR again it worked,
May the issues came back at the beginning of the month, I rang on the phone and stated what the issue was, what the solution was and what they needed to do to fix it... Reduce the INR, "We can't do that we need to send an engineer" So they sent an Engineer AFTER reducing the INR Server side, so the engineers call out was pointless.(5 Engineers so far) 
June, July, August; All the same arguements with the Tech support with the issue the same questions asking if im wired if im wireless... All the time the answers remaining the same and the fix to the fault which was reducing the INR
September; Sent out the 6th Engineer... He came around i said mate you're wasting your time i can tell you what you need to to do fix it. he said he was here to double check everything was as it should be, he phoned one of his mates who was a rain engineer they said the fault would be down the the frequency. So i called BT told them about his recommendations, to send a Rain engineer to assess the situation, Remove me from the 21CN Network back to a 20CN Network and that should fix all of the issues.. But it didnt.
October, Someone cancelled the order for the 20CN Network, order had to be redone, was given a supervisor who monitored the case, called me every 2 days to notify me of progress, said he was awaiting a reply from BT Wholesale...
November, same issues with the internet rang to find out the status of the 20CN network, Still waiting for the reply.
December, Issues returned with a vengence, 20 disconnections in the space of time of 2 hours, worst it had ever been totally unplayable, rang BT they capped my line to 3mb/s Was still laggy.
29/12; 4 more disconnections in the space of an hour, Rang 150 to the Tech support desk, the woman i spoke to said she was running line tests and everything seemed ok, i explained the problem and how frustrated i was with it, requested to be placed through to cancel my BT line, her supervisor requested to speak to me to double check her work everything seemed fine, he transfered me, i got a customer rep who said i would have to pay for the rest of the contract because i wanted to get out early, i said why should i have to pay when im not getting the service i should without having to constantly call up and tell people how to fix it. he said Tech support hadn't authorised a free disconnection, requested to go back to Tech support to ask why, he said he was passing me through, 10 minutes of listening to music before the line went dead...
Called back through to the tech support, got another guy who went through all the basic connectivity checked the line, checked the setup, how i had my wiring, if i was Ethernet, asked me if it was ok to call my mobile while he ran a line test, as he was running the first line test he couldnt see anything, then a train passed and he HEARD the magnetic interference on my mobile!!  the crackling of the signal, he then said well its enough to put out your mobile connection so im going to speak to my supervisor, I then had them both speaking to customer services regarding the issues to find out there was no chance of me ever getting a 20 CN Network because the technology is no longer in my Exchange
So my question is this... IF they cannot fix the issue by moving me over to a 20CN network, and im unable to access the fibre optic broadband due to the area, and im stuck on a connection that disconnects me everytime a train passes... What can i do as a solution, That isnt my fault its an external problem and i don't see why i should have to pay for an appauling service which i barely get.. disconnections every 30 minutes or so. 15 minutes at peak times... Should I have to peddle the responsability of paying the contract fee to get out of contract with bt because i live next to a train line? i dont think so... they cant offer me an Alternative service which would work so they can't fix the issue... which makes it THEIR Fault. not mine.
Sorry for the long post, alot to fit in and im pretty **bleep** annoyed about the whole thing

Answer 1

Sounds you have done all and more, you are right the tech team do have to refer you to cancellations, indeed to disconnected every 15 mins peak time and 30 mins standard is totally unacceptable situation to be in. 
 From personal experience I would suggest you phone back the tech team with your information you have,  read  your saga out and refuse all the normal suggestions like resetting and engineers appointments, as you have done this many times, state your cost of service and the "material loss" to you and lack of confidence in their product, they will want to try and fix the issue (LOL) they gave me 24 hrs and kept their promise of releasing me free with MAc code.I would also complain to BT by email they will contact you back, also mail Bt CEO for good measure and begin the OFCOM route.
 You do really have to play hard ball with them always be polite with them, you have been more than willing in aiding them to fix your connection and they are really now treating you as a number rather than valued customer.
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