Worst service provider

I have been waiting to return my parcel for refund with Shein since 15 March 2024. To date I have not received a call based in their poor services even after several email attempts.I have finally gone and sent my package via postnatal as suggested by Shein to Buffalo and since Tuesday 16 April I have then received callback they are not accepting my parcel??why is this..again no callback to check in with customer to date. I have never received such poor customer service. Even after paying my own courier fees they are still not able to resolve an issue initially created by them.