Dear Jack
I have heard that you have trouble in your shopping experience. I'm glad to give you a hand.
Since you want to return your mobile phone back to the seller, it's necessary to have a word with the seller and apply for returning the mobile phone. After the seller's agreement, you can call to the express deliver and ask them to bring the mobile phone back to the seller with the address provided from the seller. It will take you some days, but it doesn't matter .After the seller get the phone and check it ,you can have your refund back to you.
If you still have any other questions about it, tell me in advance. I hold the belief that I can try my best to solve your problems. Looking forward to your early reply.
Best wishes
Li Hua