My mother answered the phone and didn't get a response after she said hello several times. What is the matter with you dumb [***] calling. If you don't want to say anything then don't call PERIOD.
SSI is Survey Sampling International a company the conducts opinion polls and market research for various clients, not the Social Security Administration. Social Security calls would never show SSI anyway. SSI in the context of Social Security is an acronym for Supplemental Security Income, the disability income program. Even if you were receiving calls from a program administrator, they would not display SSI.
Here is a link to an informational webpage from the company making these calls:
As a purely research caller, they are exempt from screening numbers against the DNC list before calling but must maintain their own, internal, DNC list. The above link provides directions to be placed on their internal list.
Called to Minnesota, caller Id says 914-365-7896 unavailable, I don't answer numbers I don't know and no message left. Considering reports on other sites this is just another phishing scam using a survey as cover.