A FINRA-regulated institution is restricting my account on suspicion of identity theft and requiring that I give them a copy of my social security card which I of course don't have because what use does it even have? It has no photo or even date of birth or other identifying details so why would anyone even keep it?
Even the SSA itself suggests that it is useless and unimportant, that if you've lost it you probably don't even need to replace it. Furthermore you can even be prohibited from obtaining a replacement if you get too many in a year or your lifetime. What if you're past your quota?
In short, is it legal to require one to present their SSC as a precondition to accessing one's own funds? And corollary, are there any SEC/FINRA regulations that require an institution to demand one's SSC as identification?