Do it yourself...
A set of polishing stones and 'good' gunsmith screwdrivers - along with the ability to see and remove burring and high spots will do wonders for pretty much anything.
Follow with a 'thorough' cleaning and use a good lubricant on the moving parts - reassemble and try.
That's pretty much what they'll do, anyway - except they'll charge heavily for it, and you'll be out shipping and time.
Vaya,
Scouts Out!