Sorry Acathla, I can understand you being aggrieved at it seemingly coming 'out of the blue' like that, but NTL are compliant with the DD agreement, having sent you advance notice of the amount to be taken.
Whatever the 'pros & cons' you owe them for the line rental, if you cancel the DD they will just call in a debt collection agency, honestly, it isn't worth the hassle.
- not saying it is ideal, but in my opinion it could be a lot worse.
<edit> good advice from Marge
