1 yes you can refuse to go to police station since the 4 years has lapsed there is no proof of transaction he cannot recover the amount further no.criminal case is made out. Police in case of complaint gives you written notice.

2. There is no ground as such with him to file a case against you.

3. Since there is no agreement , and he has backed out of deal you can forefiet the amount.

The constable is just trying to pressurise you.

1) you must cooperate with investigations 

2) deny that any advance money was received by you 

3) call upon him to produce receipt of payment of advance money or any agreement entered into between the parties 

4) you can rely upon correspondence if any exchanged with the buyer wherein you reminded him to make payment for purchase of flat so that registered sale deed can be executed by you 

1.  IF the said Buyer is now in a threatening mode and involving a mere police constable,  THEN just simply refuse to admit that you have received any money or that you have ever wanted to sell the property to this good-buyer.

2.  Attend and Record above statement, ONLY & ONLY, if you receive summons duly stamped & signed by Police duty officer and go accompanied by a lawyer.

1. Yes, on the receipt of the complaint of cognizable offence the police can call and seek your presence in police station for investigation of the case.

2. The civil claim for money is time barred as 3 years has lapsed.

3. However to avoid the dispute and considering involvement of small amount of money, I would advise you to return the money and get a ' no claim' receipt from him. 

1. This is purely a civil dispute and the police has absolutely no right to intervene whatsoever. You must move the High Court to seek directions against the police. 
2. Token money is non refundable, whether you had issued receipt or not. So don't return it. Let the other party file a civil suit If he seems it fit. 

1. if you have been called by the Police, then you must co-operate and inform them about the true facts. Not going will raise suspicion

2. tell the police that it is a civil matter and the police cannot look into it. If the complainant has any grievance he can approach the civil court

3. if the buyer defaulted to pay, then the seller can forfeit the token money. However in your case there appears to be no agreement between you and buyer by which you are entitled to forfeit the money. 

If he serves you any written notice he can call you to PS.  It's better you take Anticipatory bail before going to police station. Yes it depends on the terms agreed between you parrties. During filing complaint they don't see evidence

1. If you refuse to go to police station they may implicate you in more false cases and can drag you out of your home to police station and even remand you by an order of judicial magistrate after registering a FIR.

Since you have not sold the property to the buyer, it would be unfair on your part to not to refund the amount to the buyer.

2. The police will register the case and initiate proper legal actions, you may have to challenge the same only in the trial proceedings and not before police who will not listen to your explanation.

3. If the deal is not through then it is your duty to return the advance amount after deducting administrative expenses , if any.

1) you should appear before IO. 

2)  you can deny all allegations. 

3) The police cannot interfere in any civil dispute, including that over property, unless ordered by a competent court.

NO criminal case made out. IF next time constable call, tell him to provide FIR. And notice is mandatory to call accused or witness.

Refuse to go next time and don`t agree of any such amount ever received. You are entitle to forfeit token amount.

Dear client 

1. Constable can call you there is an official complaint against you regarding any offence. 
2. Yes he can file the case but if there is no evidence of the transaction then the case is going to be in your favor.
3. You don't have to pay it back legally as buyer have taken the step back and didn't make full payment. 

Ask him for copy of complaint against you and if there is complain against you then you should go and deny his claim and give your evidence and don't give him any written assurance about returning the money 

1. As per the information mentioned in the present query, makes it clear that there is purely a private transaction between you both which is relating to the money.
2. And there is no provision in criminal law not even cheating as the language of cheating doesn’t talk about the cases wherein one has taken money and other is demanding.
3. This is a pure case of civil in nature, he need to file a recovery suit, but eventually he won’t be getting success in that also as he doesn’t have any proof nor he in within the period of limitation (3 years).
4. You should say that you have not taken any money before the Constable and if needed then file a petition for quashing of the case against you in Hon’ble High Court.
5. Rest, you are free to call me at any time for further legal assistance.