Aha!! The other day my husband got a call from a 3 digit number, 346 or something like that. He gets lots of calls from stockbrokers and investment firms that come in as "Unavailable" or "Restricted", which he chooses to ignore; they never leave a message.
The 9999999999 means restricted or blocked caller ID, so that plus the 3 digits showing on the call itself would explain this....another brokerage call, from their internal phone system (caller ID blocked) and then the particular callers extension....thanks budone! Mystery solved!