For others reading this post..... I would not send a phone back in their goofy little bubble envelope. They have got to be kidding!
1. That little envelope is a red flag for postal employees to take the phone
2. You have no assurance or insurance that it either got there or wasn't damaged with no way to recover the cost.
3. Picture that little envelope under 300 lbs of boxes at the Post Office
Send it back insured in your box with the phone in their envelop and then place it IN THE BOX.
Also make a copy of the Submission ID tag and clear tape that to your box. Include the confirmation print out you got from the website submission