I think there is a way to print a new label from your online records.
Q's label goes by parcel post which is the slowest mail option. It also relies on third party vendors to move it from place to place. It can take 10 days to reach Q. Tracking is minimal to none.
I rarely use Q's label. I can't remember the last time but I haven't ordered anything large or heavy from them in a long time.
I go to usps.com and print priority mail postage. It costs a little more but you get full tracking and it gets there in 2-3 days. You can also set up notifications so you receive emails or texts with updates and delivery confirmation. Priority mail envelopes and boxes are free at any post office location. I always keep a few on hand. I also keep my copy of the label until the return is processed.
To me, the cost of printing postage is worth it. It might be $1 or $5 more depending on what priority envelope or box is used. The peace of mind in knowing my package arrived and isn't piled in with hundreds or thousands of other returns is worth it to me.
p.s. Q is known for horribly slow returns processing so be prepared to follow up in the customer care forum in 2 weeks.