Property transaction - return of money

Hi

We cancelled a purchase of Land (Plot in a venture) as the vendor is not provinding the entire documents related to layout.  We discussed on the same and seller agreed to return the amount in 4 months and he has also sent an email stating the same from his company's email id. Now it is been more than 4 months and he is not turning up to return the amount. 

We have the originals of agreement which was done on 100rs stamp paper and amount paid receipts.

How can we get the amount back?