I expect you want an answer from a Plusnet representative. That's fine: some of them can be very helpful, and the official support channels are pretty clogged up, and apparently not so helpful. However, this is a "community" (customer?) forum, and it's not impossible that a civilian can help. It sometimes happens. So....
By your speed, you probably mean your download speed, as measured by a speedtest. (No? Something else?) What speedtest? What was your speed, and what has it dropped to?
Inevitably, you'll be asked whether you connect via wifi and ethernet. Exasperating, I know, but sometimes it makes a difference. Can wifi problems be ruled out? Are you sure it's not some problem with your wifi router (if you have one)?
Is there some information you can give that would point to a problem with your phone line (if that is how you connect)? Does your phone work (if you have one)? Is the dial tone noisy, or is there crackling when you make or get a call?
Another angle is congestion beyond the cabinet you connect to, maybe at your local exchange. If you've done a speed test via ThinkBroadBand, they do a single-threaded speed test, and also a multi-threaded one. If the single-threaded-test is significantly slower than the multi-threaded one, it sometimes indicates congestion at your exchange, or somewhere is Plusnet's network. There is a BTwholesale speed test you can do, that may shed some light on this question.
It may be that your "speed" problems arise when you stream youtube videos, or play games, rather than speedtests. It may be a huge lag in responsiveness to internet browsing (latency), or on the other hand that it takes ages to download problems (throughput). Can you shed some light on it?
I fully appreciate that you may be furious. We pay good money, and what we pay it for doesn't work properly, and we get passed from pillar to post by pseudo-distinct organisations (BT, Openreach, Plusnet,...) playing pass the parcel, and bamboozling us with jargon. BUT, there are some good Plusnet people who sometimes look at these forums, and can be genuinely helpful. Even the civilians can sometimes help. Give them/us some clues you can about the actual problem you're experiencing. Speedtest-results? Modem statistics? Any details you can supply: it's just a fact of life that broadband problems are complicated and exasperating and time-consuming to sort out. Thank our broadband regulators and politicians for that.
