It is possible that your account has been compromised, most likely due to a low complexity password.
Your address book was also most likely copied and distributed amongst the hackers for mass distribution of spam as well. This process is also very common and is hard to stop because most of the hackers are outside of the US.
Please attempt to log into your AOL account via the web interface (http://webmail.aol.com).
If you did not change your password, you cannot log in, and when you try to change your password, the security questions are unfamiliar and/or incorrect, your account may have been compromised by a hacker.I understand the steps you have taken, but I want to make sure that all avenues are covered. If you have exhausted these options, it is highly unlikely you will ever recover your account.
In any case, I would suggest to take the security measures suggested in the future to prevent a hacker from getting into your account.
Let me know if you have any questions or comments by replying to this thread. I am here to assist you! Good luck.