Here's a cheaper version to try before you send it off. No loss if it doesn't work. Go to a local hardware store that has the McGiver section of bolts, nuts, and nobs in those pull out drawers. Find the nylon spacers 1" long that fits closest to the hole in the shank (after you have removed the broken stem piece). Bring the pipe bowl in. remember: if it does fit exactly, then get the one that is a bit big. The spacer will be less than a buck.
take your hand drill and find you bit that makes a hole that fits the spaces. Drill some holes on a scrap of wood to find this out. Then drill out the broken stem hole for the spacer 1/2" deep. Glue the spacer in the stem and let it dry. If the spacer fits the shank, life is good. if it doesn't, I use my Ken lathe, whick consists of a foot of ribbon sandpaper (100ish grit), turn on the TV, wrap the paper around the stem and turn it in one direction until is fits the shank.
If it doesn't work, send off for a new stem. If it does, you are now in the club and have beat the system. It has worked for me. I will post pictures of what I did that way>
Good luck!