These problems form one of the two types of disputes with the IRS. The other type of dispute -- disagreement over tax liability -- is handled through the system established by law, United States Treasury regulations, Tax Court rules, and the procedural rules of the Internal Revenue Service. Appeals over tax liability disputes are handled through an administrative appeals process so that, where possible, tax liability disputes can be resolved without litigation. The appeals offices are located throughout the United States. Litigation of tax liability disputes may take place in the tax court, U.S. District Courts, and U.S. Claims Court. To deal with problems within the tax administration system, every IRS district has a PRP office to help taxpayers when previous contacts with other parts of the IRS have been unsuccessful. A caseworker handles each case and tries to resolve problems within 5 days. If that is not possible, the case worker keeps the taxpayer informed until the problem is resolved. PRP offices handled over 250,000 taxpayer complaints last year, most commonly about missing tax refunds, incorrect billings, or unclear computer notices. PRP is intended to be a last resort for people who have not received the response or help needed as a result of previous contacts. Most questions and problems never reach PRP. IRS policies and procedures concerning appeals are provided.