10 years back, My dad got 30000 from a financier and he returned more than 30,000 in many small part

10 years back, My dad got 30000 from a financier and he returned more than 30,000 in many small partitions whenever he met that financier. We don't know about this, like when my dad got that amount and when he returned. We got to know about this only after my father's death (my dad passed away in 2017). So we got to know about this issue when the financier came to our home and threatened us after my dad's death saying that my dad needs to give 7 lakhs to him.people who had financial contact with my dad told us that the financier got that 30,000 back, but he is using this chance to get more money from you. Financier has few papers having my dad's sign. We are very sure that the sign is not my dad's and many false statements were provided in case papers like my dad got that amount before his death and that too some 3 lakhs from the financier and 3 lacs from the financier's son. They are totally fake. But,hard truth is we don't even have our dads sign to prove..How can i proceed on this?