1) as mentioned earlier it is necessary to peruse agreement for sale entered into to advice .
2) whether in registered agreement time was essence of contract . please clarify . did it mention that payment has ot be made within 3 months ?
3) what is clause in contract regarding failure on part of purchaser to make payment?
4) is there any clause that balance amount would be paid only after you satisfy purchaser about title to the property?
5) you can issue legal notice for cancellation of agreement on failure of purchaser to pay balance amount and refund Rs 1 lakh paid .
6) deed of cancellation will have to be executed by both the parties in respect of registered agreement .
7) only then can you sell your land to third party .
8) if purchaser refuses to agree for cancellation of registered agreement for sale you can file suit for specific performance to direct purchaser to make balance payment