You ok'ed the amount before they did the repairs, right? If not, you shouldn't have paid. Why could they not replace the bearing? Why did they do something other than you told them? Remember, you're the boss.

Don't hate dealerships, hate the ones that treat you like crap.

You can probably replace the bearing yourself but I'd have a calm and planned-out conversation with the service representative you dealt with 1st. If that doesn't work, go up the ladder. Keep your cool and state your case.