If your builder has made a mistake and started building on the wrong lot, I would use that to your advantage in getting your money back.
I am so sorry about your situation. As the others have indicated find an EXPERIENCED Real Estate Attorney who will represent you and don't delay.
Sure hope that your precious baby is doing well.
They should be the go between before it got this far but you have done your
best to try and work with the builder.
Either way, it is time to contact a real estate attorney asap.
Please keep us informed.
The Eckler Team