1. No, it is not safe to enter into a new agreement , without cancelling the agreement which is expired even.
2. Yes, Mr X can use the expired agreement , as the limitation period of an agreement is 3 years legally i.e. Mr X can file a case for specific performance or recovery of paid amount to you , within the period of 3 years.
3. You can enter into an agreement with Mr X , or take a declaration from him that he has already received entire amount , and nothing is due towards you , and further must mention that the agreement executed with him earlier , which is already expired has cancelled now , and having no value in the eye of law.
- This declaration should be prepared in the presence of two witnesses.