Maarten Hi there 👋 We do not have an option to block particular merchants. Mastercard policies might allow some of them to perform charges if the card was authorised at least once.
As @Thijs mentioned, I would also advise to reach out to the merchant directly. If that does not produce any results, you can always replace the card that was used, according to this article: https://together.bunq.com/d/1974 💳
