Issues with returning replacement device

My phone was stolen a few weeks ago so i claimed for a replacement device. After a few days after receiving the device, i was able to retrieve my original phone. after going to At&t on 7/8 to have it unblocked and unsuspended, my phone kept being blocked and suspended again. I called customer service and they said asurion did not receive the device i returned. But i have sent it 7/9 with the smart label they provided through the post office. I looked online but couldn't track it. I did not get reminders to return my device and figured it was already received. It's such a hassle for my device always being suspended specially now that i have a family emergency. I don't want to get charged on a phone i returned or force to give up the phone i paid off. Its really annoying for a customer who pays  on time for years.