First, you can't contact the debtor by phone, and you can't send a letter to the residential address left at that time to repay in time. If there is no result, send a letter to the address left by the borrower with a list+warning. If there is no result, send a lawyer letter. If there is no result, sue the borrower and sue the guarantor! Before the prosecution, the guarantor will be contacted by a lawyer's letter in advance, and the relevant court will not be present to enforce the defendant's office. ...