Your subscription is tied to the hardware address of your router so if you change the router you no longer have service. When you end your contract your router is simply denied access to the network but the network is still there. With BT your line is physically disconnected to stop you accessing the network.
It is possible to reconnect your old router, but it involves taking apart both routers, so its not recommended, and you may be charged for it if VM find out as you do not own any of the equipment.
What do you mean by the hub is "dead" ? Normally when people say that and leave it disconnected for a while (as in disconnecting all cables including coax and power) it will work again in a few hours.
By the way, have you tried just the power supply from your old router?