i never received my package (shoes) i was charged. claims it was delivered. Discover Card says i need to initiate a dispute with you. Tracking number is LS055008088

Hello. Please tell me the real status of my package with tracking RE222504955CN . I need to know if it passed customs or not. I am confused why its back in Shenzhen. I have few more days left before my dispute close so i need to know if I should open dispute now. Seller keeps tellingn me its instransit. Thank you

I placed the order on Aliexpress on the 8th of February 2021.
Last status update was on the 17th of March: Shenzhen, Arrival at Shenzhen International Bulk Processing Center.
Service: China Post Registered Air Mail
AWB: RE189606145CN
I have been looking on my national post tracking service up until now and the parcel wasn't received.
It's the first time I order something from abroad. It's not something terribly valuable and I can always order more but if the post service is to blame I don't know if it's worth it or maybe I should try another delivery service.
I don't really want to dispute it as I don't think it's the seller's fault yet I have 2 days left to open dispute.
Is it still in China? Is it somewhere else in transit? Should I dispute it?
Can you guys please help?