Sale agreement

I have made agreement on 14-jun-2015, at the time builder says ''with in one month we will hand over the key'' Still now they are not giving some document to bank (i applied the home loan, Bank asking some missing document) Now i want to cancel the agreement, withdraw my 1 lac advance amount. FYI - we are not yet registered the agreement. Some points from Agreement Below 2. The sale should be completed within THREE MONTHS from the date of this Agreement, The PURCHASER has this day paid to the Vendor a sum of Rs.1,00,000/- (Rupees One Lakh only) as advance by way of Cash, and the receipt of the same is hereby acknowledged by the Vendor herein. 6. If the Vendor and PURCHASER fail to complete the sale, the PURCHASER and VENDOR shall be entitled to specific performance of the Agreement and claim, registration of the sale deed under specific performance Act. The question is: while asking reg:cancel agreement to builder, He says Okay. I will give the amount, after booking the flat How can i resolve this..