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

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.

I would like to request information regarding the reason why my shipments were returned to the sender before leaving China.
Tracking numbers: EV070476998CN and EV070511329CN
According to the China Post tracking system, both parcels appear to have been returned to the sender and never left China.
Could you please provide more information about the reason for the return?
For example, was it due to a customs declaration issue or the suspension of postal routes?
Thank you in advance for your clarification.