collection of unlawful debt

A pleasant day.. your advise is highly appreciated... years ago, I incurred a personal loan fr someone.. there is no written document on such.. I was only able to pay it all up this year by monthly installments. Now d gist: according to my debtor, she made a loan from a lending company 2 years ago and she allegedly used the money when she applied to work abroad.. Unfortunately, she returned to d phils because she had differenced with her foreign employer... because of that d lending company is running after her.. accdng to her, she gives all of my monthly payments to the lending company as her payment to her loan...and now she wants me to pay d additional interest of 24thou which was demanded by d lending company. . I refused to shoulder the interest.. now d lending company sent me a demand letter. . I know my rights and obligations.. d lending company threatens to file a charge if I don't pay up... how could that be when I am not a party to that particular loan?? I didnt personally applied or made myself a guarantor for a loan in their lending company. .. there is no signed contract involvinh me.. can I inquire on what case can I file against that lending company for forcing me to pay up for d interest of someone else's loan??? Thank you in advance... god bless