not yet. all my accounts+managed accounts under other's name got same email. will call them in a few days to see. i got the email possibly one or two months, just ignored them so far.
Here are my thoughts on this: Send a written communication (by email or by ticket) along the lines of: "regarding your reference ticket #xxxxxx, please tell me what information you are requesting so that I can have it ready." As it is from: documentsubmission@interactivebrokers.com then the hint is that they want documents. (Probably you are not "allowed" to trade other peoples accounts - somewhere in the fine print without some documents showing your permission by them to do so and probably you can't technically do it even with such documents if they feel you are doing it as a business - without being licenced to do so. ) If the other accounts are all using your mailing address then the verification of address of each of the parties of the other accounts?
So what did they asked you? And what were your responses? I got the same problem as you. Please help!!!