If the traffic that is flooding your link is unwanted traffic (code red etc...), you'll need to talk to your ISP.
If the LL is private, and not an internet line, you'll need to determine who is sending the data and get them or throw up an access list on the other router.
If the problem is with errors, and not with traffic, you'll need to contact the telco that provided the LL.
Are you trying to telnet from the local ethernet side, or from accross the LL? Have you consoled directly into the router so that you can work on it? Things like debugging being left on or a modem connected to the aux/console port that is echoing can melt a router's CPU and cause it to be unresponsive.
There isn't enough information in your question to help much. Sorry.
Mick