One of the bags I sent to Chanel was a beaten to near death heart chain bag that I bought off ebay. I posted the after pictures but since the search feature has dropped into a black hole, you can't pull it up. They worked a miracle with the purse. It came to me severely faded and dirty. Before sending it to Chanel, I sent it to Art Bag in NY. They did nothing with the purse and charged me, so don't bother with them.
My prior experiences with Chanel refurbishing bags has been quite a bit ago, and every time the bags came back looking brand new so I was ecstatic with the results.
If the bag needs to be redyed, it will have a slightly rougher feel. Isn't that better than having a rag of a bag? After all this is skin we're talking about and dying it will cause some depletion of oils. Use a purse moisturizer and then seal it. I'd trust Chanel or Luvinmybags. I like LMBr products a lot so far so I would trust them also.