How do I exchange a defective XG1v4-A box?

I turned on one of my 2 XG1v4-A boxes yesterday and noticed it was stuck on the "Welcome..." screen.  I followed every possible on-line tip including power on/off, reseating cables, powering it off for a long time, moving it around (exchanging with other box location), trying to access/reset it from a PC via internet ("unreachable"), doing a full system refresh, etc. 

No matter what, it can't get past Welcome.  It appears to be bricked for some reason (bad auto-firmware update in the middle of the night?), after working fine for 2-ish years w/o touching it.  My other XG1v4-A still works fine, as do 2 satellite X1 boxes.

I would like to exchange this XG1v4-A box for another.  How do I do this?  The on-line support options do not allow human contact or anything other than endlessly pushing the same old trouble shooting options that do nothing.  Very frustrating.  Can I bring the defective box into a nearby store and have it exchanged there, or must it be done via mail?  If by mail, how do I do that?

Thanks