Is there a 'cease' on my line?

[#1]

Just registered my details with Plusnet for a new broadband connection following the move into my new house last week. BT have given me a new number, but Plusnet is telling me there is a 'cease' on my line and they cannot initiate a new connection.
I have phoned BT several times only to be told that my line has no cease on it, is fully ADSL enabled and is clear for broadband use.
So why is this happening? Surely I should not have a cease on a new line/number? Who is telling me the truth, Plusnet or BT?

[#2]

Having looked into this, the information we have provided is correct and has infact, come direct from BT Openreach (via BT Wholesale).
As per the ticket on your account, the Cease looks to be from a previous Broadband service on the circuit assigned to your property.
As a new line owner, there are two instances this will happen.
1: The number you have has recently been stopped and the old Broadband upon it is still in the process of being stopped. This one is rare as numbers are normally taken out of service for a period before re-use.
2: Each line is assigned a circuit ID. You have had your line routed over a circuit that has only recently come out of service and again, had a previous broadband service that is still in the process of being stopped.
This can happen mainly when the previous occupant had broadband, but can also happen if the circuit assigned was at another address and recabling took place to place your line on it.
In addition to the the number/circuit recently being stopped, another common theme of the above is when people fail to cancel their broadband when they move out (or providers fail to place a Cease when they are told the customer is moving out).
There are a few ways for us to tell if a cease is in progrss versus a Tag on the line, or providers having not yet placed a cease. In your case, the indicators suggest the cease is in progress, but no specific date has been provided.
We will recheck the order anyway, but it can be anything from 5 working days to whatever date the previous provider chose as the cease date, which could be 30 days down the line.

[#3]

Thanks for the detailed response. I think your suggestion number 2. is the most likely. I know the previous occupant of the property had a Tiscali broadband connection, but this would have been on the old number (same line by the sounds of it).
It is frustrating that no date is given for the cease to end. It was suggested during a phone conversation with the helpdesk that duration was 10 days (from when I called).

[#4]

Tiscali would explain further information in the check I performed.
With some providers which includes Tiscali, we cannot get the exact date for the cease of service. Ten days is also the average for ceases from such providers.