Guido It’s in their pricing sheet as well. So nothing to complain
If you advertise something loudly and proudly on your website („That‘s it! No hidden costs.“) and then there actually are hidden costs, a complaint is par for the course. Irrespective of the amount. And irrespective of what the competition charges. The original poster was clearly not expecting it.
I obviously wouldn‘t pursue the €0.10 as everybody has got better and more important things to do (and it might actually be more expensive booking that refund). As a business owner on the receiving side (the bank in this case), I would probably still own up to my mistake and offer the refund.
But yeah, as you said, it‘s not a big deal either. I think, bunq should just change their pricing web site, and we can all move on.