You are the legal heir of your mother; hence, you have the right to mutate the property in your name. However, your name is entered in the revenue record as a legal heir of the deceased. So there will be no dispute towards heirship. After the construction of the house you will be the owner and no one will interfere in your right.
Section 18 of the Real Estate (Regulation And Development) Act, 2016 (RERA) entitles the flat buyer to claim a refund of money and compensation for any loss from the builder. If the builder did not complete the project within time he shall be liable to refund the money with interest.