Multiple unexplained charges from Amazon

Over the past 6 months Amazon Marketplace has been charging our credit card with various amounts totalling now over €400. This case has been open now for for 3 months and the charges are continuing (€66 this week). Amazon apologised and said they refunded me but I never received anything. Amazon case support have not been able to figure out the issue and have transferred the issue to the payments team which I or they have no way of contacting. My account is bleeding and I have no way to stop it.