Thanks! I've already replied to the original e-mail and will let your colleagues deal with it; if I don't get any reply I'll get back to you directly.

To clarify, I have never explicitly requested "not getting more email from you" (in fact I'm sure the unsubscribe link works fine), I just haven't opted into any e-mail in the first place besides it being mandatory to provide an e-mail address when donating, but I didn't expect it would be kept for anything other than the receipt and any legal obligations. It's most likely against the GDPR as well if you think your organisation falls under the regulation.

So my problem is less about unsubscribing from the list and more about why I was on the list in the first place which is the only reason I'm making a big deal about it.