Lost Luggage after Check In
 

I am wanting to know how my check baggage for my flight from Vancouver (YVR) to Frankfurt (FRAN) then to Malpensa (MXP) did not make it onto the plane after I checked the bag in at the flight check in counter at YVR. I've been in Italy for 5 days and my suitcase has been missing this entire time. I have just found out today my suitcase got sent to Auckland, New Zealand which makes no sense. When I had previously looked at the status of my baggage using the Lufthansa and Apple Wallet App when it did not show up at MXP, the tracking # for my bag said it was in Frankfurt. I don't understand how this can happen,

I don't understand why the tracking number said my suitcase was in Frankfurt, why the bag did not get loaded on the plane and why it was sent to New Zealand. I am very understanding person, however this situation is unacceptable. I have been very frustrated, and have been forced to deal with the situation of not knowing why this occurred, as I have been stuck without any of my belongings for 5 days.