loan to a person

i had a loan from a person whos willing to give an interest. of 40% for 2 years. i have hit rock bottom for the middle of the payment but i had been trying to pay them as much as i can but after two years i know i had still have some thing left unpaid. is it an abuse to threat me if i did not sign the agreement that in will be held and detained if i did not sign it? it is in their house where it happened as i do not have a choice but to sign it. i am willing to pay the remaining balance with all.of my capabilities but having another interest on tjat would be a burden for me. he always tells me that it is loaned on a bank but if i asked for a proof there is nothing. should i file for non tax payment for the loan business itself plus threat? i signed the document due to im forced to do so. if not im going to be held for not paying. he has a list plus i have the last 3 to 4 transaction or proof that i am not turning down my responsibility within my capabilities to pay. i do not intent to run. i just want to pay what i have loaned woth interest but of course it is too much for me if ypu want to force me to pay another interest. im not running from my obligations we just hit rockbottom as of the moment. still paying within my capabilieties. please advise.