I completed a self build and after 6 months of living in it decided that I wanted to get lodgers in my house due to the cost of living crisis, I had applied for a cil exemption as this is my main residence but have been told my exemption has been removed as i had changed it to a hmo. I've now got 28 days til my cil bill will arrive. Note I live in said residence and have 3 lodgers. What can I do, is there any way to fight back or convince council otherwise.