There are several good companies in that area. One of the best can be found at www.rekeying-locks.com/kansas_city_missouri_mo.php. They will fix any sort of lock you may have.
The electronic car lock button on my Chevy Malibu is loose, and sometimes doesn't lock the car. How expensive would it be to replace the mechanism? Is this kind of car lock repair an easy task for a do-it-yourself mechanic?
This isn't easy to do yourself, especially if a factory-installed security system is connected to the lock. You'll need a factory technician to work on it, and it will most likely cost $300 to $400, depending on where you live.