Hey, magenta2260017! Let's see if we can help figure this out! What type of return are you completing?
If you're trading in your original phone, you may be able to print the RMA label online through your MyT-Mobile account -- you can find some details here: Trade in your device. If you're completing an exchange and you need to return the original phone, then the label is on the box that we ship the replacement out in -- you should see a red line with arrows that shows you where to peel off the part with your address and there's a return label addressed to us underneath. Lastly, if you're completing a Buyer's Remorse return (you upgraded within the last few weeks but aren't satisfied with your choice, have ordered a new phone and are returning the first upgrade) in some cases we can e-mail you a printable UPS label to use, or you can simply Contact Us for the address to our Return Center. Just let me know which situation you're in and I can provide more information if you need it!
This may be a blessing in disguise. I suggest you obtain the correct mailing address (if you don't already have it) & ship the package yourself. Make sure you fully insure the package and get a receipt verifying that it has been shipped. There are a lot of horror stories about "lost" devices. If you ship the item yourself, it makes it much easier to make a claim. If you use T-Mobile's label, you're at their mercy.
Just checking in here to see how things are going with your return. Did you ever end up getting a return label?