They are blowing smoke up your ass .....
Sorry I'm being so blunt but I do admin work for a few people and have not seen any movement yet on worldcom lines people are standing firm till they see how this all plays out.
And anyways how can a host be taken down from people moving off of worldcom lines? It just don't make any sense.
For real hosting answers talk to me.
However if you like being lied to stay with your current host.
<-- worldcom causing your host downtime .... thats classic