“DSL line is disconnected” Problem

dear all,

i m using ADSL. i have dLink +2 router.
it was working fine. but now the adsl led went off. i complain to my subscriber but they said there is fine in their end … is this really my router’s fault.

how to recover if so.
and one thing .. how can i detect if my subscriber is providing me the adsl line or not ??