Sounds to me like you are part of the scam. How could someone pull off a call from the number recited....they were in that office idiot. The map point to a southern state as to where this number is from, not CA. Also, they call on one 800 number and ask you to call back on a different 800 number. I do not think so. You should have signed in as ScamMan.
I called Social Security after getting called from this number the day after I applied for SSI. It is legit. It was from the Western Region Service in Richmond, CA. Agents make these calls when they have questions about your application or need more information.
Also need to mention that 1-877-772-3794 is a total scam number..."please stay on the line for a special offer"
I do not believe the Social Security office provides 'special offers' LOL
From my experience this appears to be a legitimate number. The reason you cannot call back on it is because of the total lack of customer service in the SSA. If it became known that you could call this number and have a decent chance of actually talking to someone, the SSA in Richmond would be overwhelmed with calls. Instead they want you to call the 800-772-1213 number which often has an over 3 hour wait time. The post office does the same thing. Ever have a problem with mail delivery and tried to find the telephone number for your local post office? You won't. You will only find a national number in DC that is a waste of time. I haven't checked but I am sure the VA , IRS, and other mismanaged agencies are the same.