I think /inverse would help. Mostly because you cant report someone just from pictures of you paying them and then of your empty inventory because they could have been taken at different times. What is needed is something that will help to see what is in thief inventory AFTER money is paid. I think /invsee would help with that.
/invsee is available for Titans, though I think that would not help... Maybe add a little bit more info why? For now, No support
I don't think this would be good for reporting but good for avoiding a situation like this. You could invsee them to see if they have the item they are selling. Ask them "Do you have it?" if they lie you can cancel the offer and save you're self. Support!
Scamming is a Huge Problem in mineverse. Invsee Is going to Help 1 . KitPvp , Skyblock , prison And Mcmmo , To see if the Player is lying about the Stuff there gonna give you 2. Creative . Making sure the Person does not Clearly have a Hacked item.