Big brand ******* systems

This morning I bought 2 items from the online merchant order ***, but I got an error message that required me to " update my payment details." But my banking app notified me I'd been charged R500. This evening I got to fixing the error only to get billed the second time!! Now customer services tells me I must wait and return the unwanted items to get a refund. This is unacceptable and extremley poor service. I demand immediate refund, nothing else.