Chacom Panthere 185 with loose ring -- any advice?

Greetings,

a pipe acquisition from last year has a loose silver ring in front of the stem.
Not quite sure how to approach fixing it, if possible. When I say loose I mean it will fall off.
Inserting the stem more firmly does not help.

i can post a pic if necessary, but I figured I'd gather your initial thoughts.
I hope it is not literally defective -- too late to return to vendor.

I'm about as mechanical as a drunk toddler, so I'm hoping this is an easy, common-sense fix.

Thanks