I sent the Tax Administration a payment that was supposed to be for back taxes. It was used on a tax prepayment instead. Why?

This can happen because the reference number for your back taxes is the same as the shared reference number for all your income taxes (including prepayments and additional prepayments). This means that when you send us a payment with this reference number, we will use it on your first upcoming income tax.

Example: If you have two instalments of prepayments to pay, the first one on 24 June and the second one on 23 July, and you have back taxes due on 1 August, we will use any incoming payment first on the prepayments due in June and in July and only after that on the back taxes.