As I said before, no one pulled anything. There was no subtext in their deal, no clause you skimmed over and missed, no fine print that screws you over. It's not even a bad deal, not at all. You got a chance at three tongues, they helped you with the fight. You simply expected a safety net that wasn't there, that they had no responsibility to hold up, neither contractually, nor morally. They didn't force you into this, they didn't coerce you into this, they offered you a simple deal, they didn't say "you'll get the tongue in return for the shank", they said "you lot this, we lot that" and you agreed to that (it isn't a bad deal anyway if you just want a Behemoth Tongue).
I try to be as fair as I can, always, and I would do something like that too. It's not to screw anyone over, it's just a normal deal, I don't even understand how you can take it the wrong way. You made a mistake, no one played you, you expected something unrealistic and then backed out, which means now you got two shots at the tongue for absolutely nothing in return.