Delivery marked delivered but not received

ITT marked my parcel as delivered whereas i didn't receive any parcel they told me that my parcel was involved in hijacking but they havent contacted me and told that after the hijacking i was the one who contacted them thats when they told me about the hijacking , so i've contacted the ITT courier today ,they said they haven't done any investigation about this hijacking they don't even know the lost parcels they'll confirm to the driver ,but they **** to me when I went to their offices on the 26th of March they said the case was opened they even gave me the case number so that was just a lie there's nothing they have done about this and they even **** to buffalo logistics about me signing for the parcel ,now shein cannot refund me because my status states that my parcel have been delivered ,so contact the local courier not buffalo .