Report Junk for iMessage texts (SMS)

Since switching to xFinity Mobile, I now get many, daily SMS/text spam messages on my iPhone, and blocking each sender is pointless--most send from different numbers each time.

When will xFinity enable the SMS junk protection & reporting that most US carriers already offer with the "Report Junk" feature? I know xFinity uses the Verizon network, and I know Verizon provides this feature. So why is it not available on xFinity Mobile?

(Oddly, a week or two ago, one junk SMS displayed a "Report Junk" option, but it disappeared a day later. Maybe it's in testing? I hope?)