Whatever they did, give it back or not, their decision, sure.
I just don't get the "oh he payed RL money for that" argument.
Once someone (without any rep) insisted I go first because that someone payed RL money for that something...
Ended up going halfway first, completing the trade successfully, and then afterwards being insulted by that person for not respecting their RL money, wtf. -.-
It does NOT matter how you got it, if you payed RL cash for it, it just proves that you are either:
(chose at least one)
- bad at this game
- a showoff
- a dedicated supporter of this game
None of these make you any special though.
Again, "shop" item or not, it does not matter how you got it, it has a price ingame, and is worth whatever someone is willing to pay for it, and you wont (at least not legally) get any RL cash back for it!
Therefore there is no difference to any other item obtainable ingame.
Also, iirc, mortal moments owns ALL those items, not you.