Low speed on FTTC (2mbps)

[#1]

I have a FTTC connection and I'm still only getting 2.5mbps down and 1m up. I was assured 11mbps when it was installed. The low speed was last investigated in Nov 14 and I was assured the the 2.5 km BT copper line would be improved as this was causing the low speed.  What can I do to improve issues as I'm paying for an undelivered service?

[#2]

Where's your cab? Are you very rural?
With FTTC the copper's only used for the final leg, it's fibre to the street cabinet. Whilst you may have had a 2.5 km loop length, if the cab is closer your speed will be dictated by the quality of the copper line (do voice calls or silent tests reveal a very noisy line? (use 17070, or dial 0 and hold mute on your corded telephone to check for audible noise). I'm three miles from my exchange and tolerated 3 Mbps ADSL sync until FTTC, now I get 74 Mbps due to the cab being a few hundred metres away.
Go to the BT Wholesale speed test, run a test, this then stores it on the BT systems which PN can see. Also check the PlusNet portal "what's my speed" page and you should see what profile is on your line. The Wholesale speedtest checker will also show you this if you go through to the advanced pages. There's guides on the forum for how to see your line profile. Whilst unlikely, it may be stuck on an old DSL profile and PN need to issue a reset to get FTTC profile applied.

[#3]

The tests are linked from this post  https://community.plus.net/forum/index.php/topic,143836.0.html

[#4]

I can see that you raised a fault prior to posting on here and we'd replied advising that an issue on the phone line had been detected. Often problems with the phone faults can cause broadband issues too.