Hello. How do I speak to someone about a chargeback?

A client filed a chargeback before I could review it and refund the client. The client had asked for a credit and that was immediately given. Then they proceeded with a chargeback to their bank before they provided me with the documentation to support that the item was damaged when it arrived. The chargeback has gone through the day that I received the photos of the damage and the chargeback is for more than the product in question since multiple items are on the same invoice. There were two chargebacks done and 2 fees associated with it and I never had a chance to resolve the issue. I had no problem giving them a refund, but they had asked for a credit and said they could select another product. Then after telling them they had the credit, which was issued the day they told me about the damage, they said they meant refund. At that point, the chargeback was already in process and we didn't have a chance to even offer a refund. Now I have a chargeback, 2 chargeback fees and a chargeback for an item unrelated to the dispute. Who do I talk to about resolving this?