Seller/Builder Delaying Construction on Purpose

[Daniel Dos Anjos]

Hi,

I signed a Real Estate Purchase Agreement for a property that currently under construction. The seller/builder delayed the construction for 8 months and now he wants to raise prices claiming that homes have appreciated. I feel like he has delayed the construction just to make it passed the agreed closing date so he can make the agreement invalid and set a higher price. Is this legal? What can I do regarding this matter?

Thank you