Is adv address and client signature is mandatory in legal notice

I entered in an agreement for purchase of a house with a house owner. Owner of said property given information in agreement of sale that house is free from any loan & not mortgage anywhere while fact that at the time of agreement house was mortgaged. When I came to know the above fact I contacted with owner of house personally and over phone & requested for refund of advanced money ie 20 lakh rupees paid through cheque by me at the time of agreement. That agreement time duration was 2 months, before expiry of above agreement of sales I sent a legal notice through my advocate and clearly mention in that notice I am not willing to purchase above said property. Now today I received a counter reply of legal notice and opposite party adv is saying your legal notice is totally fake and not bounding on my client because adv address is neither available on legal notice not signed by me. Only my adv signed legal notice. And the above legal notice is not according to law. Now my question is if Advocate address not available on legal notice in that case it is invalid notice and not as per law.? IInd question is opposite party said in reply of my legal notice your advance amount forfeited and you have to pay 30000 for two month rent and rs 20 lakh for non purchase of house. Please advice on my both questions. Thanks Pradeep Dixit M. N. [deleted] Email [deleted] Whatsapp number [deleted]