Cast Iron Drain Options?

[Emmett Hawkins]

Hello BP Memphis,

My tenants reported water coming form the foundation and a slow draining sink recently.  Plumbers put a camera down the line and said that the cast iron drain has collapsed somewhere in the middle of the house and that they need to excavate through the foundation to repair the line digging up multiple rooms $$$$.  This exact repair was completed by the same plumber 8 years ago.  

I have some questions:

How long should a repair like this last?

Should I seek legal help for pressuring the original contractor into covering the repeat repair or just suck it up?

Should insurance cover this?  (Different insurance company covered most of it last time)

Do you know any cost effective plumbers that could re-route the line or insert a sleeve without destroying the floors or most of the floors?