The Billion can have vdsl disabled but it is normally enabled by default. Equally it should be in modem and router mode not be in a router only ppoe mode.
You also might try changing the adsl lead. I had (now binned) a modem lead that worked with the HG612 but not with the ECI/r or other modems. It was due to a slight defect in the plastic channels that the RJ11 connectors sit in, so basically depending on tolerances it sometimes simply failed to connect.
You could post screen shots of the settings so they can be checked.