Dublicate douments used for loan in banks and raised hands

dear sir

i have land which was given as gifted to my wife and this site has been made as a layout on 1998 and then brought from 1 seller.

now one unknow guy made documnets as cents on dated 1999 year then make documents then applied loan on 2012 , now he is not paid amount to banker /

banker came and told that hey want take necessary action on surity land .

now what to do.