I have a similar mess and am anxoous to see replies. There's a couple
other avenues you can try:

1) Mudjacking - problematic - may not be able to lift the slab

2) Topping with high density high-tech concrete. May be marketed as
Acousticrete. They prime your floor, mix up the stuff, and pump it in.
Drawbacks - expensive; weight may further depress slab.