Cantonment Freehold

Sir/ma'am I am one of the lease of shillong cantonment My father has applied for freehold to MOD in 1994 which was passed in 1995 asking my father to pay freehod amt of 53000 in which they ask my father to pay 1st installment of 13200 to which my father has paid after a year Mod has revised its amt frm 53000 to 92000 and asking my father to pay 2nd installment of 6000 to which we hav paid since then frm 1997 there was no response frm cantonment board but my father kept reminding them written every year till 2007 where my father has passed away after our father we the successor continue to give reminding letter every yr 1n 2010 cantonment board replied new rate has been revised to accept we were ignorant and accept the new rate till 2010 there was no response frm cantt but in 2018 they serve us the notice of 1800000 (eighteen lakh) in which they deduct our 19200 as a 1st and 2nd installment and asking us to pay again 1st installment of 400000 (four lakh) but we refuse to pay such amt and given letter reminding them of our last amt which was fixed in 1997 Sir /ma'am my question is 1_ there amt has increase frm 53000 to 92000 in 1996 to 1800000 in 2018 but our 1st and 2nd installment remains the same even in 2018 2_ if I go for case what will be my outcome 3_ we r financially not so strong 4 _ currently MOd has issued cantonment would merge into municipal then if I file case what will happen after merging into municipal 6_ can I get good lawyer to assist me in this case at affordable fees