NO FEED BACK AT ALL

I bought a tv set online from Amazon Market Place oversea and they send it to the post office (to my box address) We didn't get a notification that the tv was there so they send it back to the supplier in 11 May 2017. My tracking no: II ********** 88ZA. Since then I've send emails to the post office, they just pass it on and nobody can actually help me. According to the post office the supplier (Amazon) received the parcel but the supplier says he didn't get it back. My son Lance also e-mailed without any reply, he spoke with ANTHONY at Amazon Market place.... All I need from the post office is a signed proof of delivery so that Anthony can arrange my refund. Hope you can help me with this matter cause it's going on for very long time now.

Thank you