cellphoneforever did reply to my email right away, suggested some things that might help, and said that they would exchange the phone or battery, or issue a refund.

It looks like the charging problem is fixed -- it seems that it was the problem mentioned elsewhere in this forum about not recognizing when it's connected to USB after a firmware upgrade. At least I think it was after a firmware upgrade.

Anyway, putting the battery back in and holding down "u" while plugging the charger in worked. (I was trying a different charger, too -- that might have been a factor. Will test later.)