Was it vibrated and properly consolidated?
It is a slab on grade, correct? How thick is it? Is it reinforced?
So it might be 2" where it dips down? What is it supporting?
I would replace it. That's poor construction. It won't meet any spec or standard construction practice. Require it to be replaced.
You can't fix uncondilidated concrete. It will crack all over and fail long before it should. It's not acceptable construction
Hello. Do you have any other questions for me on this topic? If you could rate my answer, I would appreciate it.