I need to send my third generation 19 to Glock to have the frame checked out. The u shaped piece under the front rails that is a support is gone. Last time I shoot it with no problems, went to clean it and noticed the part is gone. Is Fed-X or Ups the best way to go, where do I take it, not to one of their stores? Do, I ship it back in the Tupperware box, do I box it up in a cardboard box or does the carrier need to do this? What do I need to put in the Tupperware case besides the G-19 and a note? This is the first time I ever sent a firearm back to the mfg. I did call Glock. Thank you for any help.