No mud underneath house...I bought a house that is about 45 years old..it is in Metairie, LA and is on a slab.

It was bought and remodeled and flipped. The inspector said I have a few perimeter voids around the slab where the mud/land subsides and it is somthing I will have to monitor on an ongoing basis. When I went to address it, I noticed/realized that I have no mud underneath my house. If I run my faucet, the water goes like a waterfall underneath my house, and there is enough space to army crawl underneath pretty much the whole thing. An estimate is between 60-85 yards of sand to be pumped at a cost of about $3000. The seller is in the clear because I signed a waiver of redhibition, and the only way is if he hid or lied about it...which I would have to prove, which I pretty much cannot. He never said anything. New plumbing pipes were installed which to me would mean someone went under the house to replace??? right? I am sending a note to the inspection company for negligence, but that would only get me about $700. Anybody have any info on this...dealt with this, any other options I have?