Affirm works with multiple business partners to provide different payment options for you and your customers. Shop Pay Installments (SPI) is powered by Affirm, but it is in fact a Shopify product. You can learn more about SPI here.
If you currently have a Shop Pay Installments integration, Shopify’s support team will be best suited to answer any inquiries you may have. You can submit a support request directly to Shopify here: https://help.shopify.com/en/questions.