Shein is useless

I ordered a parcel from them in November. I got a notification on the 5th of December (from the logistics company) that the parcel was out for delivery and that it would be delivered in 48hrs. It is now the 16th of December and the parcel has not been delivered. Shein and the logistics company Imile has not been helpful. I have requested a refund but they are urging me to wait longer. I cannot wait for this parcel any longer, it has been past the predicted delivery date