For your information, the IRS computer is continuing to generate Notices of Levy, during this IR/Government shutdown.
It's been my experience that just about every IRS fax number is not functioning, during this government shutdown and you will receive a busy signal when these IRS fax numbers are dialed. So trying to contact anyone at the IRS, by fax, is literally impossible. You can still leave phone messages, but that's not very legally proficient.
We would advise all practitioners who receive a Notice of Levy, during this government shutdown, to file a CDP hearing request, on Form 12153, within 30 days of the date of the CP 504 Notice or Letter L1058 and send this request to the IRS via certified mail with return receipt requested.
It has generally been taking between 90 – 120 days to have a CDP hearing. If the government reopens and you don't need this CDP hearing, then just revoke the request.
Please note that the statue of limitations will be extended, during the time your client’s CDP hearing request is pending.