There are several reasons why getting a replacement case won't necessarily solve the issue. One of the possible reasons are the cases and the earbuds has been factory set to exclusively communicate with each other and not other units. I don't know if this is the same for Moondrop, but this is how it works for Sony's TWS. Sony though will still provide helpful support and solutions. If you ever lost the case, you'd have to mail your earbuds back to sony or physically go to their service center so they can pair a new case with your earbuds.