The letter tells that the first payment default entry has been registered to you in Suomen Asiakastieto Oy's credit information database.
The creditor mentioned in the letter has not received your payment. If you want to know what debt or invoice caused the payment default entry, contact the creditor mentioned in the letter.
The credit information register is used e.g. for the assessment of a consumer's payment ability, when they are making purchases on or contracts with credit.