If you've had no luck with the appeals office or in court, then the IRS has no choice but to start collecting your tax debt from you. There is a separate appeals process for collections, but at this stage, you cannot challenge the validity of your tax debt, but only the methods the IRS uses to collect it. If the federal government obtains a property lien, you are entitled to a hearing immediately after you receive written notification of the lien.
The IRS is also permitted to collect outstanding taxes using levies that can result in wage garnishments and the freezing of assets in a bank account. The IRS must provide you with advance notice before it enforces a levy or a lien. When it fails to give you notice or violates other laws and procedures, then you have the right to an appeal. However, this will only delay the IRS from collecting tax from you; it will not relieve you of any liability to pay it.