So i bought a 2nd Mir pet from the shop, but i didn't know you need to do a quest or something to equip a 2nd pet... so what i did was i buy the 2nd one, got into bag cash tab, double click a few time, and suddenly one of it disappear or merged with the first one that i had.... i haven't do the quest yet still, i couldn't be bothered after the buggy issue.
According to the database, your Mir's haven't merged. They're both sitting in your Cash inventory. I will check your account for myself when you log off later.