You’ve tagged this as the wrong item. The NOW box black is the streaming device, nothing to do with the router.
Also this is a customer to customer forum, so no staff will reply to your post. Any broadband issues you have to call the broadband team. See link for number.
Before you call, try unplugging the router for a few minutes. If that fails do a factory reset to the router by holding the reset button for 15 seconds.
What lights are showing on the router?