Hextech chest bug

Well i opened a chest and received a common skin.... BOT.... but yeah thought hey dont have any essence at the moment so how about i just activate the rental. i did. and yeah it expired and when it did....well Nunu bot never came back it just FLEW OFF or 'd away or something. but i would like to know what happened or something man!! i mean it was a legendary that well i will never see again cause come on 1850.....no. but 1350 orange essence is a lot easier but nope... cant now. thanks Obama.