My friend sent me a screenshot

Russian bla-bla-bla key removed bla-bla hero of the north bla bla steam

Found a similar picture in English using google.

i saw a bunch of those packs on SG yesterday... maybe they were purchased by some fraudulent way

Looks real to me. It's the same format as the message I got.

It happened to me with the WB bundle but oh well :I
It's true dude but the thing is does it say anything else but the payment? because I don't understand Russian

There is a distinct lack of pron here, I am disappoint.

I don't speak cyka :)

ouch, sometimes trades don't work the way u want ><, that's why I only do trades through inventory now, so if something like a backcharge happens I get my traded items back

Многие уже так пострадали. Мошенники покупают игры на HumbleBundle с помощью краденных кредиток, а потом законный владелец делает отмену операции. Как итог, игры, купленные на краденные деньги, выпиливаются из библиотеки. Следующий раз пусть друг покупает ключ самостоятельно, а не у фиг знает кого.

облом :(