Soda Blasting Of Tulsa

Brought a manifold in from a classic car that I wanted soda blasted as opposed to sand blasted because of the risk of getting sand particles in fuel system and bushings. Was told that the cost was $75 per hour and I was asked "what was the minimum hours I was willing to pay for"-?! Having worked with a bead-blast system I know that the car part I brought in would take a half hour at max to have a manifold completely stripped, cleaned and detailed. I told that 1.5 hours or $100 is the max I was willing to pay. When I came to pick up the part I was told the total is $150.00 or 2 hours of work. Again, this was one part and only partially stripped of old paint and surface rust. Very poor job and a lot of excuses for not completing the job to my satisfaction. After arguing about paint left on parts ("that is not paint; that is something else...") I gave up and just paid the $150. At most, the service provided should have cost $40 - $50 and that is if it was done right.