Help resolving Schrödinger’s credit card dispute

Question: is there anything I can try to get Chase to assist me further in trying to resolve a dispute that is somehow both cancelled on their end, but accepted by the merchant on the other end?

Background of the situation I’ve been dealing with: I was charged for two identical orders from an online merchant 7 months ago. I immediately filed a dispute with Chase. I later cancelled the dispute, as the merchant said they would simply cancel the duplicate order and refund the money. I was re-billed for the charges. I told the merchant I cancelled the dispute and they requested proof. When I tried to send proof, I found that my emails were getting blocked by a spam filter so there was a delay in getting this information to them. I eventually got it through by filing a new service ticket on their website with a different email address. However, the merchant at some point accepted the dispute somehow despite Chase cancelling the dispute.

I’ve been going back and forth for months trying to sort this out. Chase has repeatedly investigated and then informed me that they’re sure the dispute was cancelled and the money was returned to the merchant’s bank. They have told me multiple times they cannot provide additional proof of this because any kind of proof would include the merchant’s private banking information.

The merchant has provided screenshots from their payment service processor, Adyen, showing that the status of my payments is “chargeback”. Based on what I’ve been able to find on Adyen’s website, this indicates that a dispute was accepted or found to be valid and the money was returned to the customer’s payment method.

Last time I spoke with Chase, they asked me to have the merchant call their merchant line to discuss this directly with them. Since I have requested this from the merchant a month ago, they have stopped replying to me. I’ve emailed multiple times with no response.

I even tried reaching out to the payment service processor this week and they replied that I need to have the merchant contact them and that they cannot help me directly, although they also said “Looking into the payments for you however, shows that you are referring to your raised disputes against the merchant which were lost.
Please note that Adyen is no longer in the flow, as the funds are taken from the merchant in question from your bank to settle these chargebacks, your bank is return these amounts to your card/account. “

Thanks for reading all of this. I appreciate any insight!