Activating phone line

[Itouch4thgen]

I have 2 phone line already installed in my house one is active and one isn't.
We are not allowed to used the active one. I contacted sky about getting the inactive one activated so that I can get sky broadband.
They said that I would have to pay £100 for a second phone line. I then went on to explain that the second one was already installed and it just needs to be activated. They do not seem to be able to understand this, so I came here.
I need to know how much it is for the second line to be activated whilst the first line stays active and undisturbed?

[seawright]

Reactivating a stopped line or installing a new telephone line for you is classed as a “New Line Provision”. As there is already an active line at the property it is Sky's policy to make a one off charge of £100 for customer's purchasing a second line. If the second line was already active with a working directory number then Sky would be able to take over the line and this charge would not apply. You might like to check what other providers will charge as you may well be able to get the line activated for less than Sky charge but there may be a minimum contract period or cancellation charge if you then wanted to transfer your service to Sky.