Advocate Notice

Dear Sir, 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 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, now as per"Advocate notice" that "That the said agreement interalia provided that said predecessor will be provided accommodation free of cost & you have transferred conveyed the self contained flat without the written consent of my client which is against the provision made in the agreement by your predecessor & my client is keeping reserve the preemptive right on the flat to get back the same in accordance with the clause stipulated in the Agreement." that is further stated that in order to comply the provision of the agreement it is necessary on your part to contact the constituted attorney of the owners within 15 days failing which my client will be constrained to su against you all for upholding their right in the appropriate court of law." What can i do? Please help me. Thanking You, JOY CHAKRABORTY