My package LZ786015936CN has been stuck as “ Shanghai, Arrival at Shanghai International Mail Exchange (via)” since April 13 after being bounced between several regional sorting centres back to back. It was supposed to be here by the 27th at the latest but instead it’s been back and forth around China since the 8th and now is stuck in Shanghai. I contacted the seller and they said they can’t do anything. Is it lost? What do I do? It’s a $70 package.

My package has been stuck since the 19th of March in SHANGHAI. I want to know who can I contact for shipment updates? Putting in mind that I have contacted my local office post and they told me it's still in SHANGHAI.
Below is the info I have from China Post:
SHANGHAI, Departed From OutWard office of exchange to - RYIADH
2020-03-19 15:11

this is the tracking number LY550370245CN. My package has been stuck in the Shanghai Exchange Station since the 21st of November and was expected to be delivered by December 10th. I haven't gotten anything yet. Something else I bought the same day same already so I am confused as to why it is stuck.