This number comes up on my caller ID as "NGG LLC".  A search of the Georgia registered businesses show a "NGG Partners LLC" was dissolved several years ago.

These people are debt collectors of some kind.  They have left messages on my machine, stating I am the subject of an "investigation", they have called and harassed family members and even a former tenant from 10+ years ago.

We don't have any outstanding debts, but we were the victim of identity theft several years ago.  We have in the past experienced low end law firms who have bought up alleged debt that is 15+ years or more old (and therefore, uncollectible) and tried to frighten/bully us into paying.  (a) it's not our debt and (b) it's old debt that is not collectible.  When I tell them to sue me, and I state I will counter sue for attempting to re-age old debt, they stop calling.

Echo above comment. Have received several calls from this number. They claim they want to send me some papers about another person by a similar name alluding to a past due debt for which there is an  impending suit.

Maybe if these people calling were more upfront regarding why they are calling or if they would leave a detailed and correct message regarding their call, they might get a better response from those they call.