FTTC connection getting Slower and slower

[#1]

I have not long upgraded to FTTC as i was fed up of REALLY poor speeds.
I was Initially happy when my FTTC was activated as it was connected at 59Mb and my download speeds were around 55-56Mb So i thought that was pretty good, then it started to get slower, so i rang plusnet, they said Nothing they could Do as it was within the first 10 days, So i said fine i will wait, But Mysteriously my line Disconnected and reconnected at 65Mb and my download speeds were 60-63mb and I thought Great..
Well that was very short lived as my connection has gotten slower and slower. My router shows my max attainable sync speed as 67mb same as on day 1 when i was first activated, My sync is down to 57Mb, my Ip profile has gone down to 55Mb and my Download speeds have gone down to 38Mb all this Despite me being connected for days on end with no disconnects. I have NO extensions on my line, NO phone connected to it, a BT version 3 filtered faceplate, Cat5e modem cable although i have tried others with same results, I have wireless turned OFF, Cat6e shielded Ethernet cable. and yet my speeds are getting worse, WHY am i paying for 80/20 and yet i am only getting 38Mb down and 13.9up
This is what plusnet currently says
High-speed Broadband
Telephone number:
[Removed]
Phone exchange:
STONEHOUSE
Estimated line speed:
67Mb (This may vary between 50.1Mb and 67Mb) - Checked on 2016-02-19 16:09:09
Current line speed:
55.4 Mb
Why has my Sync speed Dropped 10Mb in a week and my DL speeds Dropped from 60-63Mb down to 38Mb??  Im paying for 80/20 and only getting the 39Mb speeds.
I thought upgrading to FTTC my days on Crappy broadband were over...guess i was Wrong! I am just Under 200m from my Green Box So i should be getting close to my Max estimated speed, Not this Rubbish speed that i am plagued with!
I want my 65Mb ip Profile back =( it Synced at that, and stayed connected nicely at that for days, then plusnet or the Exchange did Something and now as you can See my line has gone to pot.
[Moderator's note by Mike (Mav) Customer's telephone number removed from a public forum.].

[#2]

Had an email from PN today, Telling me that they have closed my Question as i have another Question open for the same issue.. Um i do NOT have another Question open as i cant even find where to open them now!! So basicly Now they have Seen my complaint about speeds going down and decided to Close my question and ignore me..Awesome
Can someone at PN please reset my Ip Profile Back to 67Mb,or close to it, I KNOW my line can handle it as it was at 65Mb before and was working lovely for Days with no Disconnects, then Something happened at either Plusnet With their Dns servers disconnecting me or my Exchange or Something and then my Speeds went to hell, Lost 10Mb Sync and ip profile, and lost nearly half my DL speeds..

[#3]

IF  I were you I would start by reporting a broadband fault, and following the fault reporting process, thereby eliminating all possible reasons for the speed drop you are experiencing. 
Your post suggests a lot of errors on your line which could be the reason for reduced speed . In turn that suggests a physical fault or interference on your line from either an external or internal source.
All broadband services are  very vulnerable to physical and external interference and it can be very difficult job to track down the cause.
Log in to your account and start here : http://portal.plus.net/support/broadband/bbfaults/fibre-speed-troubleshooting.shtml
Report back if you need more help

[#4]

Thanks, I have just done that. I hope something is done,
I dont want to end up like it was on Adsl, when my Line was HALF the Speed of my wifes on the same package.
you See we have 2 lines in our house, BTs line comes into the house, all the way though the hall way to the Master Socket. this is the Main line in the house and has the Phone attached, and my Wifes Adsl, Because we are Both gamers, We decided to get a Second Adsl Line, the Engineer came as we left him to it, he put in a Second Master socket, which BTW isnt even securely attached to the wall properly. he ran a wire From Master socket 1 to master socket two, and then attached it at the Cabinet and there was mY second line..Well After getting my second line I was Excited and did some Speed tests., and Low and behold, My Line was HALF the Speed of my wifes actually Less than half, I could on a very rare Occasion Sync at 4mb and get DL speeds of 2.8-3Mb My wife on the other hand could Sync at 8Mb+ and DL at 7Mb all day long.
I of course Complained and an Engineer was sent out, he tested the line, saw some Errors but Said thats the way it is with second lines im afraid, there are errors on the line but they are within Bt's minimum guideline as is the speed for an Adsl line. I was VERY unhappy about this but what could i do, Bt wouldnt do a Darn thing. 
SO FINALLY FTTC came to my Green Box Which is only 200m away (well actually its a little Less but i rounded it up lol ) I Ordered it as did my Wife..I ordered the 80/20 and my wife the 39/2. My wife Syncs at 39/2 and gets 39/2 dl speeds Well bar a couple hundred kb. I first connected at 59/20 and was getting DL speeds around 52/15, then after about a week it went UP to 65/20 and i was getting DL speeds around 63/17 So yeah i was WELL happy, and it was Stable as a rock No Disconnects Nothing funny on the Line ( by funny i mean Weird slowdowns Etc) it was heaven, then One day We had a power cut, then the Line went to Pot, My Sync dropped down to 57/20, My Ip Profile went down to 55/20 amd My DL speeds went down to 38/13, SOMETIMES and i mean like in the Middle of the Night when no one is online I can sometimes get up to Mid 40's DL speeds, but its the Same old Same old, My line Started off Awesome Just like when i first got Adsl and then it just got slower and slower and slower and BT would do NOTHING. Im getting a Sense of Deja vu =(
Its Happening all over again!
Coincidently My wifes line after the Power cut. Rock flipping solid, 39/2 sync, DL speed 39/2 All day every day.....My line HAHA, Im paying for the 80/20 and the only thing i can beat her on most days is upload speeds..
Heres Hoping that PN or BT will Do something this time 😃

[#5]

I guess this is standard practice, houses here have one BT/OR cable in but it has 2 pairs and only one pair is used, is your second line the other pair?
I ask as earlier this week my neighbour was having problems with phone and broadband and OR engineer found the pair in use from our pole to his house was faulty so he reconnected him to the second pair that is ok.
I'm wondering if one of your pairs has a fault on it.

[#6]

Yes my line IS the Second pair in that One cable that comes into the house and to the master Socket/ sockets in this case.My wifes line has always run at more than Twice the Speed of Mine right from Day one, But BT Wouldnt do anything about it, Basicly saying Tough its above our minimum Specs Barely but its still above so there nothing they would do, Hopefully Now that its a FTTC connection and not just Adsl Maybe they will fix it.