Foundation warranty take over from the seller

[Jason Sung]

Hi folks, I just closed a property. I bought it off-market from Sundae.com. If you have not heard about it, it is like an auction. I bought the property based on inspection report. 

The house has foundation issue; cracks on the wall/brick and one side of living area is tilted down noticeably. A bathroom right on the spot with the foundation issue appears having issue (sewer line issue?) and has not been used for a while. It is a hoarder house that has not been maintained at all for a while. 

I found from the seller that he did foundation repair (LongHorn Foundation Repairs in DFW TX) in 2001 and the warranty is transferrable. I called the foundation company and paid $250 to transfer the warranty. They said they will share the document about the previous repair. If the current foundation issue is related with the previous repairs, it will be pretty much covered by the warranty. 

My general contractor who will help with the rehab said, however, it will be difficult to get the warranty to cover the current foundation issue. The company will do everything they can to avoid cover the warranty. Also, it is very common for foundation repair companies to delay sending anyone to the property. 

I wonder what maybe the best strategy that I can take in current situation? Also, if there is a sewer line issue, who would you recommend me to contact? I would appreciate any comment/advice. Thanks.