Scammers pretending to be SSA employees caused last year losses of at least $16.6 million. The purpose of the scam is to get the victim to send money through non-conventional methods or obtain sufficient information that could be used for identity theft or applying for loans. The FTC published a recording of a scammer telling their story to a potential victim at the end of last year. The scammer at the other end of the line explains that the call was prompted by suspicions of crime-related activities or that someone used it to apply for credit cards.
Source: https://www.bleepingcomputer.com/news/security/ftc-issue-psa-on-social-security-number-scams/