This is a little glitch that was fixed.
Sorry this is a little late
From fantage blog:
"We want to apologize for the glitch we had recently with our Rare Item Medal. There was a glitch where people were able to take advantage of the system and gain extra levels by selling and unlocking the same rare items again. Every user’s current medal level should be based on how many rare points a user currently has in their inventory. When you sell a rare item, the rare points should be lost as well since you no longer have the item. The fix is out for this glitch and everyone’s levels have been corrected now. This has caused some peoples levels to go down, but only for those who had the extra levels. In the future, we’ll try to keep the bugs and glitches to a happy minimum! =)"
Yep just want to let you guys know