I don't see how there are 10 other valves bent, I would have only expected the 2 valves in that cylinder to be bent at most. Has the truck been running bad for a while? Did all the other pistons look Okay, with no valve stamps on them?
Do you know the shop you sent them to really well, are they reputable?
Something sounds wrong, either there was more wrong with your engine than you thought or someone is taking you for a ride.
I hate to sound negative but I hope you are not taking it in the tater hole. I have heard of transmission places replacing the Manual lever position switch, changing the fluid and charging the person for a full rebuild before so, there are bad guys out there.