I'm a little confused to what the specific issue is.
Why was call barring applied? unpaid bill??
Does the OP have a problem with VM service i.e. the claimed poor connection (broadband I'm guessing) and consequently wants to cancel but now has the issue that BT will charge an extra installation fee due to the previous BT line being cut?
if you are going to rant always ensure your facts have been clearly portrayed first
seems a bit OTT for an unclear issue...well to plebs like me anyway