Outdoor Jacket Sell Jacket sent was defective, I returned it to the address they requested but never received the refund or reply from the company . Internet

I purchased an outdoor jacket on the internet worth $300. The jacket was defective, the zipper did not work. I had no idea the jacket was coming from China, so I returned the jacket to the address required. They advised me to write "Gift" on the package, which sounded suspicious to me but I did. The company Outdoor Sales Jacket had an e-mail address of sales@outdoorjacketsell.com, but e-mails to this address came back as undeliverable. There was another e-mail from the shipping company service@kuaidaexp.com who did answer but they claimed to only be the shipping company and that they could not help me with this claim. I got several notices to provide the information on the package I sent, information from the Post Office slip which i did innumerable times but I never received a clear response. They said they received many packages and they could not determine mine, which weas very identifyable. Then I never heard from them again.