If the 2nd box is active (ie. connected to VM's network & you are able to view channels on it), then you are paying for it. Ring customer services & have it removed from your account. Even if its not on your account anymore, it should be returned to VM as its their property.
Cable customer since 1993. Services: FH TV, Sky Sports & Movies (2xV6), Talk Anytime Phone, VIVID 350, Virgin PAYG Mobile