Over levelled character...

PeeOne

hi all 

throwing this question out there... 
my son decided he wanted to start playing MPQ again and downloaded it on my old IPhone that is now his... however it picked up my game and not starting from scratch.

he decided that while he was in it he would take my 5* panther from 375 where o was holding him at to championed 452... which will dramatically affect my gameplay 

. I don’t care about losing the iso used I just want him back to 375 which is part of my game strategy

would CS reverse this if asked or should I sell him off at massive losses for game sanity