1) you should send legal notice to seller that you had paid rs 1 lakh as advance for purchase of the house by cheque
2) however as title to property is not clear and marketable you have no option but to cancel the deal
3) ask seller to refund rs 1 lakh paid ad advance within period of 7 days of receipt of notice failing which you would be constrained to take legal proceedings for recovery of rs 1 lakh with interest