Our contractor was supposed to pour our 2,500 sq ft basement floor in our ICF house so that it had a smooth finish that could be stained with a concrete stain to look like marble. He completely botched the job. The floor has cracks in it, is peeling in spots, has high spots and low spots...he even left a few footprints in it. The floor has pex tubing for radiant floor heat in it so we want to avoid tearing it up and repouring it. We would still like to be able to stain the floor once it is repaired. One person suggested we tear the whole floor up and start over but we hope to find another way to fix it...maybe a thin, self leveling pour over top what is there or grinding it down or ??? Any suggestions would be appreciated, also the approximate cost per square foot to repair. Note:he is now our ex-contractor.

Greetings,
1 1/2" light weight, self leveling concrete should do the trick.

You can google for "concrete overlay".

Depending on the amount of heating required from your radiant floor and how deep of embedment of the pex tubing will help to determine the fix to your problem.

Are there self-leveling concrete overlays of differing densities? If so, seems like you would want a dense, thin overlay with good bonding for radiant as opposed to a thicker lightweight overlay.

How big are the cracks?

An acrylic overlay could be applied. In doing this you'll be able to fill the depressions and choose the color you'd like also. It will probably cost same as a self leveler.
The humidity level created by the concrete toping will be 100%, therefor numerous fans and several days to dry out the product will be required and I don't believe the marble look will be as achieveable as regular concrete since the self leveler is not polished and does not comprise of the same aggregates.
The acrilic toping will also need venting from the off gasing but not as long as the concrete toping.
Regarding loosing ceiling height, is it a problem?

A simple solution could also be grinding a small section and then acid stain. You'll see a lot more of the agreggates so will "kinda" look like a pebbled floor. Concrete grinders can be rented at almost any rental or big box stores.

Where are you located?

An overlay is going to be much more affordable than replacement (obviously). But when you say you want to stain it, what is it you're looking for? If you just want a uniform floor that's a uniform stained color that's "concrete, you can use a self-levelling grout. It's mostly cement and sand, so that's what it'll look like, ground or not.
Most people want the ground, polished, stained concrete. That will include being able to see the ground aggregate. Likely the 1 1/2" self-levelling overlay that rbisys1 suggested will work well but will likely have no larger than 1/2" aggregate. If you'll want the full concrete look, you'll have to go between 2" and 3".

Keep in mind that you can select your aggregate for different looks!

But you mentioned that you have cracks. Keeping in mind that all concrete cracks, how bad are they, and what is the reason/ cause? If you simply overlay, the cracks will likely reflect through unless you take preventive or mitigative measures. Too many variables, and too many options to suggest on this one.

Thank you everyone for your suggestions... i appreciate your taking the time to help. To answer your questions...The cracks are not very wide but run the entire width of the rooms. Brock put no control joints in at all and the workmanship is atrocious. He claims it was too hot when he poured and his men had little experience with concrete. We have 8 foot ceilings so we don't want to give up too much height. We are located on the Eastern Shore of Virginia. Does any of this change any of your suggestions? Thank you again.