Fibre Optic Extra - Speeds dropped!

[#1]

I've been on Plusnet Fibre Extra for a few weeks now and i've had the same speeds and its never changed which have been 73, 74 and 75mb phoned them up today 40 minutes until I got answered to find out system were down but he said my IP Profile just needs changing and the guy would call me back, Never got a call back, so phoned again later on today and was on waiting for 1 hour 3 minutes until someone answered, he said my line is 66 - 70mb and the ip doesnt need changing as Fibre works differently well im not too happy about it and here are my Results that I did use to have:
http://www.speedtest.net/my-result/4903477999
http://www.speedtest.net/my-result/4910595409
http://www.speedtest.net/my-result/4910595409
http://www.speedtest.net/my-result/4907510529
So why have I dropped to this now? I'm not really happy to be honest with ya    50.27mb
http://www.speedtest.net/my-result/4924333532
http://www.speedtest.net/my-result/4924338309
There must be a fault, my speed wouldn't just drop like that?
[Moderator's note by Dick(Strat) Line removed which breaks this forum rule.

[#2]

Hi, In reply to your speed drop this is a common practice with PlusNet, they get you to sign up for 18 months then shortly after they drop your line speed. For 3 years I enjoyed a download speed of 72.5 this has now dropped to 61.9 and after two months of emails they stated that they could do no more, as for phoning them that is a waste of time unless your prepared to wait 30+ minutes hanging on the phone and that idiot stating every few minutes stating that all are operatives are busy.
They have just brought out a new router which if you search the item it states that it is rubbish

[#3]

already being discussed here http://forums.thinkbroadband.com/plusnet/f/4454231-plusnet-fibre-extra-speed-dropped.html#Post445430... and the reason explained