I got this call myself and I laughed because I'm a paralegal and I know better. According to the law, specifically The Fair Debt Collections Practices Act (FDCPA), a debt collector MUST identify themselves and notify the consumer that the communication you are receiving is from a debt collector and an attempt to collect a debt, and that any information obtained will be exclusively used in the collection of that debt. They must recite these words pretty much verbatim. So to not stress yourself, if they don't, just hang up and don't give it another thought. If you really want to pursue or report the matter, the agency charged with enforcing the Act is the Consumer Financial Protection Bureau and you can can go to their website www.consumerfinance.gov or call them if you wish 855-411=2372 but their office is mainly focused on protecting consumers from real companies and collection agencies that are breaking the law by going beyond what they are allowed to do by the FDCPA, however I'm sure they are most likely already well aware of this number but will still be happy to take your complaint.