sample notice against epf and esic default contractor

We are a Pvt ltd Company and availed services from a manpower contractor. We have regularly paid wages of the employees. In the month of December 2018 it has come to our notice that the contractor has defaulted the epf and esic contribution of the employees. We have terminated his contract based on breach of contract terms and non compliance of epf and esic dues to the govt authorities. He has sent a reply stating some bald and evasive reasons. We want to send a legal notice to them.