Cheque To Builder

I have decided to book a flat and given cheque to the builder for holding that unit. I wanted to purchase that flat on my mother name. I have signed the application form in Co-Applicant. The builder had en-cashed my Cheque without taking any sign from my mother. Without Signing, the created Tax demand on my Mothers name and now they are saying that the will forfeit my money if I will not pay the demand. Blocking amount cheque was given by me and not my mother. Can you please help me with this situation. Can a builder forfeit such money without the first applicant sign? Is that form is a valid contract. Such form has a forfeiture clause. Thank you