Basically...

[#1]

I have a page asking for my log-in details, until then I can't go online.
I know it sounds stupid, you'll be thinking just enter them?!
I have, & it says they're wrong.. But I know my details, trust me you'd never forget 'em lol..
Any ideas?

[#2]

Is that the router login as that isn't your normal Plusnet login

[#3]

It asks for my username, the same of which I log in to plus.net itself, to view bills ect.
Update:
This is the page I get, if it's any help?
https://www.plus.net/apps/getstarted?switchIP=212.159.6.23&ip=10.49.21.175&vid=0001&vd=PlusNet&authT...

[#4]

If you go to http://192.168.1.25 can you check the password and username as it sounds as though the router is playing silly beggars with the auto setup

[#5]

Hi Danielle,
It should be sorted now. It's because the account was in a cancelled state. Unfortunately it looks like a request to reverse that came in a little late.
I've re-enabled your account and have cancelled any orders we had in place to disconnect your service.
Let me know if there's any further problems with that.
Adam

[#6]

Something else has just arisen.
I can see that your next billing date is set to tomorrow (which I know is wrong) we're not able to change that I'm afraid. However I will refund the bill straight away for you.
Sorry for the hassle.

[#7]

Hi Danielle, just letting you know that you've not been billed just yet so I'll go back and check this later in the afternoon.