Hello. I sent back a package from the United Kingdom to go to China but it is stuck in Shenzhen customs since the 18th January 2025. The tracking code is LB213107275GB. On the China Postal Express & Logistics website it says that my parcel's last movement was on the 25th March 2025 and it was "In-Transit Shenzhen,Returned, Please Contact XXX Customs Agency, Tel:" but I do not know who to contact.
So far I have not been contacted by anyone about this. Could you please advise what to do. Thank you

On October 19, I sent a package to Shenzhen. November 10, 2022 My parcel was sent by mail for customs clearance at Shenzhen customs. For 48 days now, customs clearance has been going on. The status of the parcel does not change. The addressee of the parcel in Shenzhen claims that he did not receive any messages. What can be done to deliver the parcel to the addressee?

I purchased a duvet set from an English retailer that I was unaware was to be delivered from China. The goods arrived on 28.4.24 and were unsuitable. I, therefore, returned the items by Royal Mail on 7 May 24 and have been tracking and chasing ever since. The parcel has not yet been returned to the supplier, being stuck in Customs in Souzhou. I now know that I should have been advised by the Post Office that a completed customs form should have been attached to the parcel, which it was not as unaware. I suspect this is why the parcel is still noted as held in customs when I track it. My problem is how do I rectify this with Chinese customs to enable return and refund to the supply. Any advice/help very gratefully received please.