After reading through all 4 pages, I understand where the seller is coming from. It's like sending your Vios to another workshop, and after they failed to fix the problems, you send your car back to Toyota Service Center. I doubt Toyota will honor the warranty anymore since it's been tampered before by a 3rd party. Same goes here. Seller will not entertain for a refund because it has been tampered before by a phone shop before and the possibility of swapping with a faulty unit exist, or tampering of phone internal circuit is there. (note, I'm not accusing buyer of anything).

My 2 cents