You can:  

• dispute an overpayment decision if you have been asked to pay back tax credits 

• disagree with a tax credits decision if you think your tax credits are wrong 

• make a complaint if you think you have been treated unfairly 

Call the helpline first if you think HM Revenue and Customs (HMRC) made a mistake.  

For further information on Tax credit appeals and complaints, see GOV.UK's website.