please help with the curse of the graverobber hook (first time GM)

Hi,

so as a group mostly consisted of new players we have picked up D&D, after a medium short starter campaign I decided to branch into odyssey since every1 wanted to keep playing their characters and we had a blast so far.

Last session my players encounter the graverobber and bought the cursed amulet despite knowing its origins. They did benefit greatly from its power in battle. They plan to bypass the curse by selling the amulet among each other each time they need to eat, which kinda caught me offguard since the source material didn’t really cover this. I would very much like keep the curse as a hook for the metropolis.

My next session is tomorrow and since they use a long rest at the end of last session, I need to address the issue now. Would you guys kindly point out some options that are logical how I can keep the curse as an actual motivator/issue for them to solve? I dont mind them buying some time with their solution but the curse shouldn’t be solved so easily with a workaround like that, every1 on this continent would know of this “exploit” by now.

Sorry for my bad English, looking for some advice 😊