Receiver’s country Customs won’t release the parcel. The last tracking status is: 境外进口海关留存待验(限制进口的物品-进口许可证丢失/不适用)
I have asked the customs to return to sender, but customs is saying that the sender has to ask from their side.
I contacted the sender, but they are saying they don’t know how to do this.
How can the sender ask the parcel to be returned? What is the process. Parcel sent by EMS China Post

I was tracking my parcel for an item i ordered and Tracking status of my parcel shows “Returned to Sender” last July 29. And as per inquiry with you last Aug 1 you told me it was returned to sender because it couldn’t pass the Customs. How many days will it take for the sender to receive back the item. I’m trying to ask for a refund from the seller and they told me they still need to get the item back before they can process the refund. Thanks

Tracking no.: LP006557605CN

UW653021468CN. Please help me with why my parcel keeps on being returned once it enters Shanghai. Why can’t it pass the custom check? What should I do to stop this cycle? This is already the 6th time again. Sender is providing no help and telling me to wait but it has not even moved from China. I’ve already contacted sender but what I want is to figure out how to break this cycle of returns. Can anyone please provide a solution for me/sender to get my parcel moving??? Thank you very much.