Amazon Refund Not Issued After Returned Kindle Oasis Shipment

I purchased a Kindle Oasis from Amazon US and returned it via the Amazon website. The return was sent back on March 25, 2026 under return reference TRN - 3677925-8188668. I have proof that the Kindle Oasis was returned, however I am now being told that it was not received. Despite having followed the return instructions and having documentation showing that I sent the product back, my account has still not been credited, and the return is being treated as if it never happened. This situation is causing inconvenience because I complied with the return process in good faith, and I am now left without either the device or my money. I request that my return be properly investigated based on the return reference and my proof of return, and that the corresponding refund/credit for the Kindle Oasis be issued to my Amazon account as soon as possible.