Prescribed debt collection

I had a loan 13 years back and i lost my job and stayed home for couple of years without any income. Now they keep calling and harrasing me with VSF attorneys. Its 13 years back , what i know is that when 3years passes without any form of contact the debt get prescribed. Now they are threatening me . I told the Rsf attorneys that i dont know them and i had no business with them and i owe them nothing but still keeps on threatening me