Hello Beat
We do not have any entries for the refund. I tried three times and three times got a success message without entries in the notification table.
We dont have firewall blocking and we see IPNs coming from Ogone for payments.
As I said on my post regarding ingenico slimpay, recurring paiements do not work with this gateway, nor for credit cards or slimpay or bank transfer.
We have direct link and alias activated though.
Maybe that this refund problem is also linked ?
Mind to have a look, we are going crazy with this gateway