Extremely Bad Service - time after time

The worst company - no assistance from their call centre. I regularly import stuff from Shein - unfortunately they often use this non reliable company. I have had numerous complains with them. Once they delivered my parcel to someone else - they literally just pulled up their shoulders, after first trying to convince me they did deliver it to me and then showing where I signed for it, but it was not my signature - not even my name or surname! Today the call centre told me that they can only help me if my parcel did not arrive in the next 3 days - before that they cannot do anything. When I asked to speak to a manager or supervisor, Chris, the call centre assistant just told me I may not and put the phone down!!!!!!!!!!