Ok, here is my 2 cents on the matter. Anytime you send any knife in for warranty work, you need to include a few extra steps beyond boxing it up and including the prerequisite form. You need to include a handwritten or typed note (if you write like a preschooler), and explain exactly what the perceived issues are, no matter how obvious they may or may not be.
Bullet points man, in your note. It helps also to write on the actual blade at times (do not sharpen). Else how they supposed to know what you want:
Here is an example:
On a clean sheet of paper:
First- put your name and address in the upper left corner. Include email address and phone number, RMA number you were given, and the make, model, serial number of your knife.
Second- outline what you are sending the knife in for. Broken blade, resharpening, replace screws (be specific).
Third- equally important is to outline what you DO NOT want done to the knife. Do NOT sharpen blade.
Fourth- include a blurb given the people fixing your stuff to call you if anything strange appears.
Simple stuff that I've always done.