Land classification

I approached DTCP in Tamil Nadu to get approval for my existing building, they rejected my application with reply of Land classification in revenue record is Wetland, so must get NOC from District Collector. I argued with officer that there's no agriculture in my village and its coastal salt area, and Tamil Nadu registration department details showing land classification is RESIDENTIAL CLASS 2 TYPE 1, and they collected stamp duty according to residential class about 80000, the same area land with wet channel classification is just 1900 rupees. It means i already paid the development charges to the government as stamp duty. The officer not agree with me and he insist on NOC from collector. When I approached collector office, they said it will take around years and need lacs. My goodness, even my land not worth for it. How they fixing guideline value and classification, definitely after visiting the land , then how two classification arriving here for same land. Please guide me to get the proper approval my building. Thank you.