Contact Steam support and submit ticket.
Word it like this.
Hi. I paid $9.99 (USD) on xx/07/2015 for a ‘merc’ (playable character) named ‘Phantom’ in the game Dirty Bomb.
For whatever reason, a small portion of the community for this game were outraged at the addition of this character. Due to that, the developer of this game has recently changed the way this character works, basically making him unusable.
I feel that this is a blatant cash grab, and is against both the ethics and TOS of steam.
I request that you refund me the money that I used to purchase this character.
I will not be spending any more money on the game Dirty Bomb, now that their underhand, unethical business practices have been revealed.
Thanks for your time.
Once Steam have received 100 complaints of this nature, the game will be removed from Steam, ala WarZ.
Remember people, this is your hard earned money. Would you let somebody come up and take $10 out of your wallet? LOL no you’d punch them in the face.
Best of luck all.