Issue with house construction permission

I have a property with single storey RCC house. I have some space(around 8 feet) left at rear side. I want to utilize a part of that space(5.5 feet) and also build the 2nd floor. So i spoke to a contractor and they have already started digging and setup the house post at the back. I also applied for the house construction permission through a guy who works in local Development Authority(DA) and I have got the acknowledgement receipt after he submitting the required documents in DA office. The engineer form the Jorhat Development Authority came to my house and has asked me to stop that construction as there has to be a minimum space left at the back. But when I got the acknowledgement receipt the DA guy who told me that I can start the work and now he is lying that he said to start building the upper floor. What are the options available for me now? I am really stuck. Coz I already filled the base with concrete and have the iron bars already set there. Can I apply for commercial permission now ? Do we also need to leave space in in that scenario? Please guide.