Do not answer. Will not I D who they are. Should be reported to FTC.GOV. It is unlawful to call and not say what this is regarding. They should have their number flagged and warn people to BEWARE. It will be reported (888) 978-6922 and (214) 380-2043.
It's some kind of collection agency. Leaves a message on your vm (even if you do not state who you are in your message, which is illegal) stating: "(Your Name) please call us at ********* or have your attorney call us to settle this matter. We have left numerous messages and need to speak with you immediately."