It's really dissapointing to see so many people on this site complaining that the website for printing a label for equipment returns is not working, yet still no response from Comcast to either fix it or provide another solution. They state plainly on their website:
Our Response to Coronavirus (COVID-19): We are now offering you the option of free UPS Pickup. Schedule your at-home pickup by calling 1-800-PICK-UPS. As always, you can also return your devices at a UPS Store or hand your package to your local UPS driver.
I've even called to get a pre-paid label but after many minutes on the phone, no one knew how it worked and just said "go to the nearest UPS store". It's great to tout a service, but only if it works.