Investment with signed documents as proof

Good day.. Ask lang po if paano ba namin ma recover yung money na na invest sa kakilala namin. Nag invest po kami ng pera sa kakilala namin tapos pinapahiram niya sa mga borrowers na kakilala niya (allegedly businessmen). Meron po kaming contract (unnotarized) stipulating an amount invested and the interest rate and maturity date rin ng investment. At first okey naman yung transaction, but starting October 2016 hindi na siya ngbibigay na interest and yung principal amount gusto na sana namin kunin pero hindi nya maibigay kasi hindi pa daw nagbabayad yong mga borrowers niya. Pa help po sana about this, pls give pa advice po ano dapat namin gawin para mabalik yong pera.