Make it clear in your notice to the LLC that you need its Employer ID number on that W-9, not the SSN of a member. Some of these folks don't seem to get or pay attention to the advice they should be getting from their accountants. Unfortunately, the optimal time to get the EIN is when the first account is being opened (when you can leverage the ability to say "No.") Now, your only leverage (aside from nagging) is the implicit threat to toss out the account(s), which is most likely not something you'd want to do.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8