What is going on is that often Plusnet order FTTC connection, and only when that has successfully completed do they order line transfer from the existing Service Provider.
What shows on your Order History? Does it show an outstanding order for the phone transfer?
(I'm reading your post as saying your phone was not with Plusnet when your were on ADSL).
Correct I was with BT as it was easiest way to get line installed into new property but their broadband didn't look as good for my needs.
The Account Summary shows an order on date I placed upgrade request - but marked as complete (this may be related to static IP requested just after), the view order status link from their seems related to original order - but I see nothing else outstanding - If I go to upgrade page there is a message about upgrade pending so I can't change anything.
One of the questions says
9:22am, Monday 11 May 2015
Provisioning of your ADSL Account Information
Action 21CN Modify Submitted cleared
Modify order has been completed
I did use talk to online assistant Thursday who said should be ordered in 48 hours - I can see nothing to suggest it has
and wondering if got in a hole in system
Nostalgia is memory with the pain removed