Need Advice: Builder Sold Project Without RERA Approval – Refund Not Given

I am seeking guidance from legal experts and anyone who has faced a similar situation. In 2024, I invested in a project near Vrindavan Highway, UP. It was advertised as “soon to be RERA approved,” with assurance that if approval was not obtained within 6 months, the full refund with 12% interest would be given. Payment was made directly to the builder’s company account. Sales were handled through a marketing agency; the builder never interacted with buyers. The project never received RERA approval. Later, one partner passed away and the other was unwell. The land was reportedly sold to a third party without informing buyers. The marketing agency now says they are not liable but are trying to recover funds from the new owner. Can I legally claim a refund with interest? Who is liable — builder or marketing agency? Can this be pursued under RERA, Consumer Court, civil suit, or criminal complaint? What is the most practical legal route? Thank you