Late payment

I have purchased 2BHK ready to move flat from land owner of one of the Big project in Ravet, Pune. Agreement was done between me and owner for 20% own contribution and 80% Bank loan. Payment made and agreement dates are as below: 2 May- Rs 100000 Booking amount cheque was given to Builder. ( Not deposited by builder till 16th Aug due to unknown reason) 18 May- Rs 7,56, 900 cheque given- Bounced due to insufficient balence and noticed very late by both owner and me by 14th Aug. 25 May- Registration agreement was done. 16th Aug- 1 lac +7lac=Rs 8,56,900 payment cleared. 24 th Aug - Loan processing was completed. 27th Aug- Loan disbursement was done 35lac. 26 may till 27 Aug- 3 months loan got delayed. Builder has forcefully planted his agent from SBI to process loan. He has initiated very slow loan processing. Till 15 Jul he has not done even my verification at home and company address. I have done his complaint hence builder has agreed to do loan processing with my reference loan agent. He has filled my case and within 15 days got the file approved from SBI with few queries. Conveyance deed, sales deed, builder NOC etc. Builder not agreed to provide conveyance deed and sales deed stating project was not completed. hence he has filled loan in Swargate branch and loan was got approved and 100 % disbursement done to owner. After repetive follow up owner delated possession. Now he is asking for late fees with 6% rate of interest for 3 months. He has pushed all allegations on me stating you have delayed loan and not supported his previous agent for loan processing as a result payment got delayed. Since flat ready to move he is asking for 100% payment should have been done within 7 days of agreement. Please let me know if this is legal first of all? I have not been given any written notice or verbal notice of delay in payment. Rate of interest is correct? What options I have to file complaint? It is like owner has waited till 100% payment has been received and post that forcefully asking for 6% rate of interest and not giving possession.