1) issue legal notice to seller to execute registered sale deed in your favour for other 3 plots 

2) if he refuses file suit for specific performance against seller 

3) also file police complaint against seller for cheating , criminal breach of trust under section 406, 420 of IPC 

You can file a suit of specific performance in the civil court against the seller to register the said plots in your favour as that is agreed between you and you had already paid the amount. 

Further register a FIR against the seller for cheating breach of trust and intimidation in the concerned police station. 

If you have valid proof regarding full payment, a cheating case can be filed at concerned police station.

You can file a civil suit as well for the specif performance of contract and and interim injuction to restrict the land lord from alienating the property or to sell it to some one else so as to defeat your case. 

1) You can compromise with him and get registration on your name or resale the plot to third party by making tripartite agreement and ask him to come for signature in sub registrar office.

Seller is bound to register the deed at the agreed price. Give a notice to the seller to register the within 30 days and to be present at registry office on s convinieni date for registration. Also give a copy of the same to the register along with an application for registering the deed in absence of the the seller in the event the seller fails to attend the registry office for registration of the deed within the said 30 days. The registrar will register the deed on expiry of 30 days in absence of the seller.

OPTIONS:

1.  Sell the Land and capitalize the profits, instead of indulging in legal disputes /litigation's with the developer /seller.

2. You can file a Police FIR, requesting investigation and charge-sheet, for offences like cheating, intimidation, fraud against the person, supported with all relevant supporting documents.

3. IF the Police does not take action, THEN you can file private criminal case u/s 156(3) Cr.P.C., in the local Magistrates court, seeking directions to the Police to investigate and file charge sheet. The said Person may come down for settlement.

You can obtain court orders to direct seller to execute registered sale deed in your favour 

See if there is agreement and you have preformed you part of same then the court shall order to register the land in your favour.

You can file a suit for specific performance and get a decree to get it registered

Dear Client,

What documents you have. POA with consideration or without ? Plots are in your possession, Avoid the seller or complain to police if he threats or harass.

Have you executed agreement to sell.

Dear Sir,

You are purchased the plots is in pursuance of a contract, with the seller. So, both of you are bound by the terms of contract. He cannot go against the contract and you have been paid the money, He cannot hope that the buyer will return it as the contract is in your favour. Further, the contract is signed and you have made payment in acceptance of the contract. Hence, repudiation is difficult.

If did not agree for the same, then you get issue a legal notice after that file a suit in Civil Court for Specific performance of contract

Suit For Specific Performance of Contract in India. Specific performance is a remedy developed by principle of equity. A party to a contract who is damaged because the contract is breached by another party has the option to file a suit forspecific performance compelling to perform his part of contract.

The unregistered sale agreement or buying the property based on same irrelevant documents will not confer any right to you to fight the case in the court of law also.

However based on the transaction details you may file a suit for specific performance of contract and await the court's decision on this 

Yes, you can file a suit for specific performance of contract for the other plots which have not been registered n your name based on the financial transactions taken place between you both