I can attest that writing directly to a company president with a complaint can work wonders. One should try to exhaust other options first, of course, so one can write, "I did this and this and this and this and still no satisfaction, and no sign of any, so can you help me out?"
Another option for your friend may be to try to buy a replacement gear elsewhere, always assuming it's a stock (or modifiable from stock) gear he needs.
Try to make a living, not a killing. -- Utah Phillips
Don't believe everything you know. -- Bumper sticker
Everybody is ignorant, only on different subjects. -- Will Rogers
There are lots of people who mistake their imagination for their memory. - Josh Billings
Law of Logical Argument - Anything is possible if you don't know what you are talking about.