Return deadline & HODL withdraw

[mrowcp]

One of my customers (amazon US) open return request, which I accepted.
I have paid for return label and attach it to the apology message that I've sent. It has been more than a week without answer from the buyer. Meanwhile I try to reach him a few times (any one with this problem: "Your e-mail(s) to USER lqlq@marketplace.amazon.com cannot be delivered because there was a problem with the recipient's email system. The recipient can still view the message in their message center on amazon.com, but they will not receive it by e-mail. We apologize for the inconvenience.")
1) Аs far as I know there is no deadline for returning? If so, can I escalate case to amazon or is there another way to close this case?
2) Can I hold/stop the scheduled funds withdraw? If money go to my bank account, they will be converted to my local currency, than when I issue refund, they will be converted again to USD and I will lose money.

[SaiJin]

Maybe the buyer changed his mind about returning it?

I don't think there's an unlimited time that they can return items on Amazon. It's usually a month and if after that they don't do anything, the claim closes from what I have seen being a customer myself

[Beautiful]

I believe its 30 days, I would keep trying to reach out to the buyer and hope he responds sooner