True. U were greedy to get 3% per month means u desired 36% on money lent while TN has interest Act too.
your is like Shylock's idea
You can file to recover your 3 lacs with normal permissible interest , pleading you did nor know what is right interest i could get, it is upto court to grant you what interest you can get on your principal moneys lent as you did lend your moneys but when he signed as borrower he did not tell you what interest is permissible as he had intention to get your money to meet his ends so he kept quiet and signed the stamp paper which if you registered at sub registrar office that office would have corrected your idea of interest but appears you wanted to save registration charges'
today people are penny wise but pound foolish. Had you consulted a lawyer by paying him fee after all he studies law and advises do u think he does not deserve fees!
that is the problem of today men