You might be overpaid tax credits if:
there’s a change in your circumstances - even if you report the change on time
you or HM Revenue and Customs (HMRC) make a mistake
you do not renew your tax credits on time
HMRC will write to tell you what you owe and how to repay the money. Call HMRC if you:
think they made a mistake
want to know how they calculated your overpayment
If you still get tax credits or are now getting Universal Credit, the money you owe will usually be taken from your future payments.
If you no longer get tax credits and have not made a claim for Universal Credit, you’ll have to pay HMRC directly. The money may be recovered from you in another way if you do not repay HMRC in time.