From what you mention it sounds like the ID encounter some issues with suppliers or manpower once the work start. Can you share the name of the ID and how are their ratings on hometrust? If they have been consistently good the current covid situation might have pushed them to use alternative and perhaps lesser quality materials and manpower.

Regarding the termination penalty that is not stated in the contract, it should be in your right to not pay since it was not mentioned and written down implicitly in the contract. Can also see legal action but not sure if the trouble and expenses is worth it.