Shockingly bad service

I ordered items from Temu and paid Buffalo International Logistics twice for vat and customs. I did receive my parcel but emailed them and sent proof to them of my double payment. They seem to think that because I received my parcel they don't have to refund me for the second payment. I have tried to phone but cannot get hold of anyone. There is absolutely no customer service!!! I don't know how they still stay in business!!! I will never shop anywhere that uses Buffalo International Logistics! They're the worst courier service I've ever dealt with!!!