Hello, I have sent my parcel from France. When I check the tracking of my package, it tells me that it is delivered, but the

The recipient tells me that there is nothing in the mail if you help.
the tracking number: CC740604366EN

Dear China Post,

I sent a parcel from Beijing, China to Paris, France on September 14th. It arrived in France but no notification was sent and unfortunately, it was sent back to China. I don't know its status and location at the moment.
Could you please help me retrieve this parcel as it is important to me? Where is it and how can it be sent back to France?
Many thanks

Hello Sir / Madam,
The parcel has been suspended at the custom office since March 19th, it is a parcel sent from France to China, I bought the product inside for my family, the transporter in France said the parcel was suspended because the invoice is not attached to the parcel, the merchant who sent the parcel in France said the invoice was with the parcel, if you can tell me the procedure to follow I can ask them to send you the invoice. Looking forward to hearing from you soon for the instructions, thanks a lot :)