can you please get through the steps to follow generate the return label.I just sent mine with with no issues yesterday (and it was signed for today) using FedEX. Did you make an online account with FedEx?
I was able to do a commercial invoice by in the packaging & shipment detail section:
package contents - documents
document description - immigration papers
Shipment purpose - personal use
Total customs value - $1.00
This then generated a commercial invoice for me. I also clicked 'create a return label' so that it was all done at once.