They just called the house and left a spiel on voicemail wanting a return call or . They're not a 'scam' so much as a bottom-feeding debt collection agency. see: https://www.lemberglaw.com/monarch-recovery-management-collections-complaints/
They buy debt for pennies on the $ and then try to go collect it themselves. The problem is their techniques involve bothering a legion of uninvolved people trying to find the right one. They may even get someone who doesn't owe anything to pay something to make them go away. I've encountered this type of lame detective work before, and had to get the State of Texas involved to shut a similar debt collection effort down. There are lawyers out there teaching others how to do this stuff, but they don't teach them well enough nor focus on impacts to the innocent bystanders: the guy I had to take action to shut down was one of them. Now I'll just block their number and if they are too persistent by calling on other numbers, I'll get the State involved again. Check your state's consumer protection laws. Chances are there is a department to go to for info or help if the collection agency gets too aggressive..
