From what I understand, Matrix is an authorized partner with Humana/Medicare. If they call you it is because someone at your number is or used to be in their system and on Medicare. If no one in your home is on Medicare then they have someone from an older iteration of your number (before you it was assigned to you) or a wrong number. I am on Medicare due to a disability and Matrix offers medical assistance services through Humana to improve home care for individuals on Medicare. Most of their clients are aged or disabled and a home visit can mean the difference between serious health issues going undetected or improved care. All you need to do is decline assistance, or let them know no one at your number is currently on Medicare and that should end the calls. Often, I guess, the reason they cannot leave a detailed message is due to HIPPA laws (Health Insurance Portability and Accountability Act), because if their records do not show authorization to leave message, they cannot, or it is an automated dialer that waits to detect human interaction. That's a best guess though. From the Humana website: "Teaming up with trusted partners. The In-home Health and Well-being Assessment takes about 60 minutes and is performed by one of our trusted healthcare provider partners. These include CenseoHealth, Matrix Medical, Your Home Advantage, Advance Health, and Peak." (https://www.humana.com/medicare-support/benef ... ome-assessments) It is not a scam, but it is a business working with Humana to provide in-home medical assessments.