No refund by builder causing delay in loan repayment

Hello, I've purchased an apartment in 2012 & made around 80% of the payment to the builder till mid 2013. The property was under construction till that time. I've taken loan from LIC for the same. In late 2013, I've started to sell my apartment and contacted to builder to either buy back or sell it to some other party. In 2015, Builder has done an agreement with me that he will sell that apartment and will pay back 50+ Lakh in installments and also given me post dated cheques. After 2 months he asked me to hold for some time and don't put cheques in bank and will pay my emis till the property is sold. He even started paying my emis but always told me that property market is low so he is unable to sell the apartment till Aug 2016 when I got to know that he has given my apartment to an agency to clear his dues. Now, he is telling that I need to wait more till he get funds from other source. I've running loan for the same which he has already sold to other. Please help me. Thx