I'd want an engineer to say why it's sinking, and what it will take to correct it, permanently.
A sinkhole can ruin your whole day.

Thank you, Randy. I'll start asking around for an engineer in our area.

Here's a few other things to consider:

Damaged plumbing pipes in/under the slab.

Cracked drywall.

Damaged flooring (when they go through the slab to pump in concrete).

Rigid flooring such as ceramic tile may be damaged during the jacking process.

I really don't think $2000 is very realistic. My sister had it done on a 1250 sq ft house and it was close to 20,000.