Very upset/disappointed with terrible attitude and...

Question

I write this as almost a last resort after almost pulling all my hair out with BT. 
I had reported a fault of low speeds to house on the 11th November. I realised after trying to download a file for an update the internet slowed down to almost a dial up speed. According to the estimated speedtests we should receive from BT we were expecting to see speeds between 9-11mbps. For the past 2 years without realising what we "could" have we have received 2mbps.. 
So I began to lodge a complaint which eventually discovered a local area fault (God knows since when has this occured) and BT said they could book an engineer to fix the fault at the exchange and it would be free of charge due to it being external. I booked the slot and confirmed with the advisor that it would not be necessary for the engineer to come into the house as I would be out. The advisor confirmed this so I felt confident that the internet would be improved. But this is BT! Of course there would be a disaster in the tail.. 
Although the house wasn't empty due to my brother opting to work from home on his project via an online portal, the engineer turned up. Knocked on the door to tell my brother he was here to fix the fault and would need to come inside after doing some work outside. The engineer proceeded to disconnect the broadband without telling him, causing him to lose all his work. My brother rang me to tell me what had happened and said the engineer wanted to come inside. I told my brother that he didn't need to but was then told by my brother that the engineer just wanted to test the socket. I allowed the engineer to test the socket.. now when we say test if "test" means rip the old socket out damaging the wall, the plaster and the skirting to stick a new socket on AGAIN WITHOUT asking for any permission. I caught the engineer as I came home from work myself and asked how he had got on, he said he wasn't from the area but he claimed the issue was fixed. This was all done on the 15th November.
On the 16th, we did a speedtest after he left and found we had gone up from 2 to 3mbps and then it plummeted all the way down to 0.01 - 0.5. I was furious. After several calls to BT they sent another engineer out to look at the damage and confirmed the engineer before had NOT fixed the problem. But BT had dispatched the wrong engineer this time and he said he could not touch the socket. Again we went through the terrible service and I spoke to supervisors/managers whoever was the "next one up" from the person I spoke to.
We had another engineer come out to test the line and told us to ask for a line reset (whatever that is) which when we put to BT they refused to do. We were constantly lied to as we were told they were monitoring the line/escalting it all with no avail. We called them out on it several times with no consistency to the story. This continued for another week where we used the service socket to access speeds of 12mbps?! However running a cable down the stairs from the service socket to the hub upstairs looks messy and we should not have to do it, so we reverted back to poor internet speeds. 
The time taken off work soon caught up with me and I gave in for a few days. 
AFTER ALL THAT, BT admitted there had been an error and they'd throttled our speeds too far and we were restored to 3mbps. This was finally done around early December. Now on Christmas Day, the problem reappears with my youngest brother who wanted to play on his new games console with his friends cannot use the internet as the speeds are too low. 
I actually wonder how BT survive on terrible service. We've noticed our complaint has been closed WITHOUT them even asking if the problem has fully gone. We've had to start a new one now and are now considering legal action. This is a total disgrace due to;
1. Paying for a service that's not being properly maintained.
2. Paying for a service that is below par what we should expect.
3. Damage to our property by Openreach on behalf of BT.
4. Time wasted due to BT's inability to organise a simple job.
5. The lack of care/sympathy/compassion shown in any of the situations. 
I cannot wait for fibreoptic to arrive here, straight switch to Virgin to avoid this complete mess. If anyone is willing to help solve these issues, please get in touch. Otherwise it's going to escalate and BT will have no defence. 

Answer 1

Welcome to this customer to customer help forum.
This sounds like a fault in your own internal wiring, especially if you say that it works from the "test" socket.
Quote " This continued for another week where we used the service socket to access speeds of 12mbps?! However running a cable down the stairs from the service socket to the hub upstairs looks messy and we should not have to do it, so we reverted back to poor internet speeds"
BT would not be responsible for any internal wiring issue, as their responsibility ends at the test socket.
Internal extension wiring is known to cause problems.
If the last technician fiitted a new master socket which looks like one of these pictures.
or 
Then your home hub will only work if its plugged into the small socket on the front. The extensions would no longer carry the broadband signal.
This help page from BT should give you a guide as to what you need to do.
http://bt.custhelp.com/app/hub/c/346,4740
There is also some additional help on this website.
Investigating speed and connection issues.
There are some useful help pages here, for BT Broadband customers only, on my personal website.
BT Broadband customers - help with broadband, WiFi, networking, e-mail and phones.