Builder not paying bank loan interest as he promised

Hello, I purchased a 2bhk flat in ghaziabad in No EMI plan till possession in oct 2013. For which i took 21 lakhs loan from bank. My EMI will be start from feb 2016 ( also the possession time). But recently i got two notice from bank telling that the bulder didn't paid any interest amount since the begining ( from oct 2013) and bank telling me to pay that amount sumed upto about 3.5 lakhs till date. Then, i asked builder about that so he told me that there is some issue with bank and they will pay it soon. So i followed him from 2-3 months about that but he's always procrastining that with new excuses every time. And now he's ignoring my calls. So my questions is that 1.what legal action should i take against him? 2. And does bank have right to notice me to recover that interest? 3.And it seem like that the possession will also delayed. So in that case what should i do? and how? Should i start giving bank EMI before possession or not? Please give me some legal advises about this problem. And tell me how to file case against him in consumer forum and what documents should i needed for that.