Debojit From Mumbai want legal help in Bank/Check Bounce/Fraud

I have taken loan from Upward Capital Pvt ltd,in month of March 22,my one EMI was due.Because of that they have started to calling and WhatsApp to all the contact and saying “DEBOJIT HAS GIVEN YOUR NAME”(which they have stored at the time of application).Because of this illegal activity,I have raised voice and requested them to provide official apology letter in company letterhead for their illegal activity otherwise I will not give any due payment.They still socially harrashing me and disturbing all my contact illegal.Now I want to send them defamation notice for their activity

Loan amount remaining -30,000 only