threatening whatsapp’s constant harassment

every month i get a threatening whatsapp message from this company yet i have never received one phone call, one letter and never have i ever paid them anything but every month a threatening whatsapp message about handing me over to court and paying legal fees ect… bottom line is don’t use this company as they obviously have bad management and very incorrect information as they have my number but don’t have a clue who i am. when i phone and give my I’d number they havnt a clue. pathetic management maybe even ownership!!!