Speed dropped since i had a warning email referring to last month usage

[#1]

I had a warning email one hour into my new usage month about light restrictions being applied to my connection speeds.
Since i have received the email, my download speed has been around 200 kbps
Before I got the email my speed was around 3600 kbps.
Despite me asking Plusnet to be honest and tell me if  I am being capped no one will answer the question
I have done the BT speedtest, three times, which clearly shows a slower connection
Yet Plusnet now seemed to have gone back to their old ways after months of good service.
My ticket does not get answered for days on end
What is going on?
Can somebody tell me
I have even bought a new "N" router and still I am around 200kbps
Soulsville

[#2]

Hi there,
I don't personally think that your speeds were capped into your new billing period.
If the CSC had made a profile or service offer change on your account, they would have told you.  If there was a problem with your line being capped, they would also have told you.  There's a chance that it was related to the dropping connections they were talking to you about, but I'm afraid there's not much I can do now as it appears to be fixed?