There are handling fees for credit card transactions, and credit card companies rely on handling fees to survive. There is no handling fee, and the credit card company does not need to open it;

You said there was no handling fee before payment, because the seller opened the credit card payment function. In the seller's shop with this function, the handling fee for your purchase is paid by the seller, so you don't have any formalities. There is no credit card payment shop, and the handling fee is paid by the buyer, so this is your situation now. When you use a credit card to shop in a supermarket, there is usually a handling fee, but it is all borne by the merchant.

When you open a large credit card payment shop, you will see the icon of credit card payment on the product information page.