Parcel says delivered but i haven't received it.

Its been 23 days without my parcel. It says its been delivered yet I haven't received it. I honestly regret ordering. They say it will take seven days to investigate yet i reported it to them 3 days ago. Mind you I'm leaving where I currently stay for the holidays. First it was the flight delay, then the driver **** about not reaching me, now it says my parcel was delivered yet I haven't received it. They are not helping me at all. They are being vague, they are not explaing whether my parcel is held up somewhere, or is still going to be delivered. They insist it was delivered, when I ask for proof of my signature, they dont respond. I keep on writing tickets which are not helping me at all. Courier logistics insists it was delivered but how can you deliver without me signing because I never signed for anything, never received anything. SHEIN said they won't issue me a refund for the missing parcel or deliver it. Guess my money went down the drain and I was ****med by SHEIN. I've ordered before from my previous phone and had no problems or issues. Now they are ****ming me. They refuse to issue my refund, I'm tired of writing tickets that are of no help at all. Customer service is HORRIBLE!!