Why do Horizon BCBS need my SSN to give me a deadline?

I called Horizon BCBS of New Jersey to get the deadline to submit FSA claims. The call center rep asked for my SSN, name and date of birth just to give me this information.

Why do they need that to give me a deadline?

Other answer:

Because there is a federal deadline, that must be complied with.
But companies are also allowed to make an earlier deadline. They use your SSN because that is the tracking number between your company and BCBS. They needed to make sure they were giving you the accurate deadline for your employer.
Because it's not the same deadline for everyone, and they keep track by SSN. They need your SSN so that they can look up which of the many different deadlines is the right one for you.
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Pork-chop of Doom:
Those are verification questions….just to check you is who you says you am…
Beverly S:
They have to look you up.