– Contact the customer and ask to restart the router not reset.
– Log into ICUK portal.
– Select the customer
– Scroll down on the screen and select Knowledge-based Diagnostics.
– Select NEW KBD.
– Run the test.
If there is a line problem it will show and you can raise the issue to BT directly from here.
A video has been saved to explain this procedure in the Support folder under the name ICUK ADSL Broadband.