Shein and Couriers Poor service

We asked to return items that was poor quality Shein then send the courier to come pick up the items after 2 weeks of waiting for the courier they finally picked up the package, then couple of weeks pass without any correspondence only to find out that the driver never booked in the package , we confronted the courier company they where very arrogant rep**** its our word against theirs. How is it that Shein treats customers this way and uses sub standard courier companies. Will never buy anything from them again !!!