Advocate Notice

My father was one of the Tenant & in respect of Development of the said premises entered into an agreement (through Notary/Notarial Certificate) with Constituted Attorney/Developer(1st part)interalia provided that he will be provided accommodation free of cost & transferring/Selling to others shall obtain written permission from the party of the 1st part. After my father died 2006 all legal heirs(03) nominated me & my wife through Affidavit before the Executive magistrate 1st Class & original of the same also has been given to 1st party & receiving copy with us & then sale deed executed between 1st part & me & my wife as full consideration money a sum of Rs one lac only through Cheque & same also mentioned in deeds & our 03 legal heirs also signed the same deed & after wards i have mutation the property & sell the property through sale of deed to other's party& present owner also mutation the property. Can legal heirs transfer the property in such way?& Advocate notice has been received from 1st part that “ you have transferred the said flat without the consent of the 1st part.”