Update to framing issues

Posting an update to the prior post. Unfortunately while at work today, work on our house continued. The slab was pored today without insulation under the slab. This is plainly specified in the contract. No insulation on the sidewalls, which was missed last week. No response to framing issue seen in the above pictures (concrete wall was not directly under the house). Can’t get a response by email or phone. They sent me an invoice today for 20k which would make them 80 percent paid. I’m planning to call the building inspector and withholding payment until we discuss the plans to fix or change the contract. I know that could put them in a tough spot. Wondering what people think is reasonable.